Stereoscopic endoscope objective lens system having a plurality of front lens groups and one common rear lens group

ABSTRACT

A stereoscopic endoscope comprises an elongate inserted section, an illuminating light system, an objective optical system at the distal end of the inserted section for forming a plurality of images having parallax between them through a plurality of incident pupils, and a common relay lens system for transmitting the plurality of images to the proximal end of the inserted section. The objective optical system includes a plurality of front lens groups and a rear lens group, wherein the plurality of front lens groups comprise two negative lens units arranged in parallel with each other and the rear lens group comprises a single positive lens group. The two negative lens units are arranged to be substantially symmetrically concentric about an optical axis of the single positive lens group and spaced to be afocal. This arrangement allows the plurality of images having parallax between them to be substantially superimposed on one another for transmission by the common relay lens system or for reception by electronic image pickup devices.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a stereoendoscope wherein images havingpassed through plural incident pupils are transmitted by common relayoptical systems so that an observation providing a stereo-feel may bepossible.

2. Description of the Related Art

Recently, particularly in the surgical field, there is known a so-calledendoscope operation wherein, in order to reduce the burden on thepatient, without opening the abdomen, a small hole is made in theabdominal part, and an endoscope is inserted through the hole for theobservation and treatment. In this field, the operation has been alreadymade by directly and stereoscopically viewing the affected part withboth eyes and therefore, even in the endoscope operation,stereo-inspection is strongly desired. If the stereo-inspection can bemade, the operation will be easy, the operation time will be reduced andthe hardship on the patient will be further reduced.

As a stereo-inspection endoscope whereby stereo-inspection is possible,there is a first related art example suggested in a Japanese patentapplication No.309078/1992 shown in FIG. 1A wherein two identicaloptical systems are arranged in parallel and the images formed by theobjective optical systems 401 and 401' are transmitted for apredetermined distance by the transmitting optical systems 402 and 402'(in this case, relay lens systems) and are taken by such image takingdevices 403 and 403' as CCD's.

The taken pair of the right and left images are converted to electricalsignals and are displayed in a TV monitor (not illustrated). At thistime, when the displayed right and left images are switched at a highspeed and simultaneously shutter spectacles synchronized with the imagesare used, the image for the right eye will be observed with the righteye and the image for the left eye will be observed with the left eye soas to be able to be stereo-inspected.

Also, as another type stereoendoscope, there is a second related artexample suggested in a Japanese patent application No.28278/1993 shownin FIG. 2A wherein the objective optical system 414 and the relay lenssystem 415 which is a transmitting optical system are formed of oneaxially symmetrical optical system. A prism 416 is arranged at the rearend of the relay lens system 415 and a pair of right and left imageshaving a parallax are formed and taken in the image taking devices 417and 417' by spatially dividing the pupil into two with the prism. FIGS.1B and 2B on the left side of FIGS. 1A and 2A show respective incidentpupils.

In order to make a stereo-inspection, it is necessary to obtain a pairof right and left images having a parallax from each other. Therefor,the incident pupil for the right image of the optical system and theincident pupil for the left image must be spatially separated. Also, themagnitude of the stereo-feel in the case of the stereo-inspection isproportional to the center distance between the right and left incidentpupils.

In the two above-mentioned related art examples, in the case of thefirst type in which the same two optical systems are arranged, when theobjective optical systems 401 and 401' to the image taking means 403 and403' are separately formed and the left and right incident pupils 407and 407' are separately positioned, images having a parallax from eachother will be obtained. The center distance d between the left and rightincident pupils 407 and 407' coincides with the optical axis distance Dbetween the left and right objective optical systems 407 and 407'.

In the second type in which the pupil is divided among theabove-mentioned related art, the objective optical system 414 andtransmitting optical system 415 are formed of one axially symmetricaloptical system and the pupil is one in this part but, when this onepupil is spatially divided into two by the pupil dividing means (in theabove mentioned case, the pupil dividing prism) 416 and respectiveimages are produced, images having a parallax from each other will beobtained. The center distance d between the left and right incidentpupils 418 and 418' is 1/2 the size of the incident pupil 419 of theobjective lens.

In the type in which the same two optical systems are arranged, as it isformed of separate right and left parts, the number of the parts ishigh, thereby increasing the difficulty in assembly. Also, themagnification difference between the right and left images due to theerrors of the respective parts is large, the displacement of thefocusing position is large, the normal stereo-inspection cannot be madeand therefore a fine adjustment is necessary.

In the type of dividing pupil, there are advantages that the partscommon to the right and left light paths are many, the number of partsis low and the displacement of the right and left images can be madesmall. On the other hand, when compared with the same thickness, themagnitude of the parallax will be smaller than in the first type and asufficient stereo-feel will be difficult to obtain. That is to say,there is a problem in that the center distance between the right andleft incident pupils is difficult to make large. This point shall beexplained with reference to FIGS. 3A to 4B.

FIG. 3A is a magnified view of the objective optical system on thedistal end side of the first related art example. FIG. 3B shows itsincident pupil. Also, FIG. 4A is a magnified view of the objectiveoptical system on the distal end side of the second related art example.FIG. 4B shows its incident pupil.

In the type in which the same two optical systems are arranged, that is,the first related art example, against the inside diameter Φ of theobjective lens frame 421 of the endoscope distal end 420, the opticalaxis distance between the right and left objective optical systems issubstantially Φ/2. Therefore, the center distance between the right andleft incident pupils 407 and 407' is also substantially Φ/2.

On the other hand, in the type in which the pupil is divided, againstthe inside diameter Φ of the objective lens frame 421 at the endoscopedistal end 420, the diameter of the incident pupil 419 of the objectiveoptical system is smaller than Φ, because the incident pupil of theobjective optical system is smaller than the pupil of the relay lenssystem as the NA of the endoscope is limited by the outside diameter ofthe relay lens system and the picture angle of the objective opticalsystem is larger than of the relay lens system.

Therefore, the center distance between the right and left incidentpupils is less then Φ/2 and is usually about Φ/6 to Φ/10. Therefore, inthis type, the magnitude of the parallax is about 1/3 that in the abovementioned type. Particularly, when the distal end is thin, no sufficientstereo-feel will be obtained.

SUMMARY OF THE INVENTION

In view of such circumstances, an object of this invention is to providea stereoendoscope wherein, as in the type in which the pupil is divided,the commonality of parts for the right and left light paths is made ashigh as possible, the variations of the right and left images by theproduction errors or the like can be made few and images having astereo-feel by a parallax as great as of the type in which the same twooptical systems are arranged are obtained.

The stereoendoscope of the present invention comprises an objectiveoptical system which has a plurality of incident pupils formed indifferent positions and forms a plurality of images passing through theincident pupils and having a parallax from each other and a common imagetransmitting optical system which transmits the plurality of imageshaving a parallax from each other.

When thus formed, as the objective optical system has a plurality ofindependent incident pupils, irrespective of the size of the diameter ofthe incident pupil of the objective optical system, the parallax will beable to be made large. Also, as the plurality of images and pupils arenot separately transmitted by the plurality of transmitting systems butare transmitted by the common image transmitting optical system, thenumber of parts will be able to be reduced. Even if a production erroris present in the individual image transmitting optical system, as theimages are transmitted by the common image transmitting system, thevariation between the plurality of transmitted images will be able to bereduced.

In order to realize such formation, there are the following two systems(a) and (b):

(a) A formation comprising an objective optical system which forms aplurality of images having parallaxes in spatially separated positionsand one image transmitting optical system which transmits the pluralityof incident pupils and the plurality of images of the object opticalsystem so that the images transmitted by this image transmitting opticalsystem may be taken finally by one or more image taking means. Morespecifically, the system includes:

A stereoendoscope having an objective optical system, image transmittingoptical system and image taking device, where the objective opticalsystem comprises a plurality of optical systems arranged in parallel andforms a plurality of images having a parallax from each other and theimage transmitting optical system comprises an optical system arrangedalong one optical axis and transmits a plurality of images formed by theobjective optical system.

In this formation, as the operation common to (a) and (b) is made andthe image transmitted by the image transmitting optical system is alsospatially separated, the image can be stereo-inspected through an imagetaking means taking images or an ocular optical system makingobservation with the naked eyes. The image taking means can use one ormore image taking devices and can take a plurality of images transmittedand spatially separated by the transmitting optical system andstereo-inspection is thereby possible.

The other formation realizing such formation is as follows:

(b) A formation comprising an objective optical system forming aplurality of images having parallaxes where they spatially substantiallycoincide (superimposed), jetting pupils corresponding to the pluralityof incident pupils of the objective optical system and one imagetransmitting optical system transmitting the plurality of images,wherein the images transmitted by the image transmitting optical systemare taken finally by one or more image taking means.

More specifically the system includes:

A stereoendoscope having an objective optical system, image transmittingoptical system and image taking device, where the objective opticalsystem comprises a plurality of front group optical systems arranged inparallel to take in a plurality of images having a parallax from eachother and rear group optical systems arranged so as to be on the sameoptical axis as of the image transmitting optical system and formingimages of beams from the plurality of front group optical systems wherethe beams are substantially superimposed. The image transmitting opticalsystem transmits the plurality of images formed by the rear groupoptical systems, having a parallax from each other and substantiallysuperimposed. The jetting pupils of the objective optical system.

In this formation, because a common operation is made and images havingparallaxes are transmitted to be formed where they are substantiallysuperimposed, the diameter of the relay optical system can be madesmall.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B show a first related art example, where FIG. 1A is aformation view showing its stereoendoscope and FIG. 1B is an explanatoryview showing incident pupils.

FIGS. 2A and 2B show a second related art example, where FIG. 2A is aformation view showing its stereoendoscope and FIG. 2B is an explanatoryview showing an incident pupil.

FIG. 3A is a magnified sectioned view of an objective optical systempart on the distal end side of the first related art example and FIG. 3Bis an explanatory view showing incident pupils of FIG. 3A.

FIG. 4A is a magnified sectioned view of an objective optical systempart on the distal end side of the second related art example and FIG.4B is an explanatory view showing an incident pupil of FIG. 4A.

FIGS. 5 and 6 relate to the first embodiment of the present invention,where FIG. 5 is a formation view showing the whole of a stereoendoscopeapparatus provided with the first embodiment and

FIG. 6 is a formation view showing an image taking optical system in thestereoendoscope of the first embodiment of the present invention.

FIG. 7 is a formation view showing an image taking optical system in thesecond embodiment of the present invention.

FIG. 8 is a formation view showing an image taking optical system in thethird embodiment of the present invention.

FIG. 9 is an explanatory view showing an arrangement example of an imagetaking device.

FIGS. 10A and 10B relate to a modification of the third embodiment,where FIG. 10A is an explanatory view showing images formed by anobjective optical system and relay optical system and a final image bythe image transmission and FIG. 10B is an explanatory view showing thearrangement of a final image and an image taking device arranged in theposition in case the objective optical system and relay optical systemof FIG. 10A are used.

FIG. 11 is a formation view showing an image taking optical system inthe fourth embodiment of the present invention.

FIG. 12 is a formation view showing an image taking optical system inthe fifth embodiment of the present invention.

FIG. 13 is a formation view showing an image taking optical system inthe sixth embodiment of the present invention.

FIG. 14 is a formation view showing a main part of an image takingoptical system in the seventh embodiment of the present invention.

FIGS. 15A and 15B relate to the eighth embodiment of the presentinvention, where FIG. 15A is a plan view showing an objective opticalsystem and FIG. 15B is a side view showing the objective optical system.

FIGS. 16A and 16B show the ninth embodiment of the present invention,where FIG. 16A is a plan view showing a unit formation of the ninthembodiment and FIG. 16B is a side view of FIG. 16A.

FIGS. 16C and 16D show a first modification of the ninth embodiment,where FIG. 16C is a plan view showing a unit formation of the firstmodification and FIG. 16D is a side view of FIG. 16C as an ocularadapter is connected.

FIGS. 17A to 17C are explanatory views respectively showing unitformations in the second to fourth modifications of the ninthembodiment.

FIGS. 18A to 18E are views respectively showing formations of objectiveoptical system units.

FIGS. 19A to 19D are views respectively showing formations of relayoptical system units.

FIG. 20 is a formation view showing an image taking optical system inthe tenth embodiment of the present invention.

FIG. 21 is a formation view showing an image taking optical system inthe eleventh embodiment of the present invention.

FIG. 22 is a formation view showing an image taking optical system inthe twelfth embodiment of the present invention.

FIGS. 23A to 23D show a meniscus lens in a modification of the twelfthembodiment, where FIG. 23A is a sectioned plan view and FIG. 23B is aside view as seen from the side of FIG. 23A. FIGS. 23C and 23D arerespectively a front view and back view as seen from the front surfaceand back surface sides.

FIG. 24 is a formation view showing an image taking optical system inthe thirteenth embodiment of the present invention.

FIG. 25 is a formation view showing a main part of an image takingoptical system in the fourteenth embodiment of the present invention.

FIGS. 26A and 26B show an objective optical system in the fifteenthembodiment of the present invention, where FIG. 26A is a plan view andFIG. 26B is a side view.

FIGS. 27A and 27B show an objective optical system in a modification ofthe fifteenth embodiment, where FIG. 27A is a plan view and FIG. 27B isa side view.

FIGS. 28A and 28B show an image taking optical system in the sixteenthembodiment, where FIG. 28A is a plan view and FIG. 28B is a side view.

FIGS. 29A and 29B show an image taking optical system in the seventeenthembodiment, where FIG. 29A is a plan view and FIG. 29B is a side view.

FIGS. 30A to 30G are explanatory views respectively showing unitformations of the eighteenth embodiment.

FIG. 31A to 31F are views respectively showing actual formations offront group units.

FIG. 32A to 32F are views respectively showing concrete formations ofobjective optical system units.

FIG. 33A to 33D are sectioned views respectively showing formations ofrear group and relay lens system units.

FIGS. 34A and 34B relate to the nineteenth embodiment of the presentinvention, where FIG. 34A is a general formation view of astereoendoscope apparatus provided with the nineteenth embodiment andFIG. 34B is a view of the arrangement of an objective optical system onthe distal end surface of the stereoendoscope of the nineteenthembodiment.

FIGS. 35A to 35C relate to the twentieth embodiment of the presentinvention and FIG. 35A is a view showing the formation of astereoendoscope of the twentieth embodiment. FIG. 35B is an elevationshowing the arrangement of an objective optical system as seen from thedistal end surface and FIG. 35C is an explanatory view showing thearrangement of an image taking device as seen from the distal end side.

FIGS. 36A to 36F show the formation on the distal end side of thetwenty-first embodiment of the present invention, where FIG. 36A is avertically sectioned view; FIG. 36B is an elevation of FIG. 36A;

FIG. 36C is a horizontally sectioned view;

FIG. 36D is an elevation of FIG. 36B;

FIG. 36E is a horizontally sectioned view; and

FIG. 36F is an elevation of FIG. 36F.

FIGS. 37A and 37B show the formation on the distal end side of thetwenty-second embodiment of the present invention, where FIG. 37A is avertically sectioned view and FIG. 37B is an elevation of FIG. 37A.

FIGS. 38A and 38B relate to a prior example, where FIG. 38A is aformation view showing the formation of an objective optical system in astereoendoscope of the prior example and FIG. 38B is an explanatory viewof a power arrangement for the objective optical system of FIG. 38A.

FIGS. 39 to 42 relate to the twenty-third embodiment of the presentinvention, where FIG. 39 is a general formation view of astereoendoscope apparatus provided with the twenty-third embodiment;

FIG. 40 is a formation view of an image taking optical system includingthe objective optical system in the stereoendoscope of the twenty-thirdembodiment;

FIG. 41 is an explanatory view of a power arrangement of the objectiveoptical system of FIG. 40; and

FIG. 42 is a sectioned view showing a frame structure at the distal endof the stereoendoscope in FIG. 39.

FIG. 43 is a formation view of the objective optical system and imagetransmitting optical system relating to the twenty-fourth embodiment ofthe present invention.

FIG. 44 is a formation view of the objective optical system in thetwenty-fifth embodiment of the present invention.

FIG. 45 is a formation view of the image transmitting optical systemincluding the objective optical system in FIG. 44.

FIGS. 46 to 48 relate to the twenty-sixth embodiment, where FIG. 46 is ageneral formation view of an endoscope apparatus;

FIG. 47A is a formation view of a plurality of visual field directiontype endoscope;

FIG. 47B is a view showing the formation of a brightness diaphragm; and

FIG. 48 is a formation view of an objective optical system utilizing apupil division.

FIGS. 49A to 54 relate to the twenty-seventh embodiment, where FIG. 49Ais a formation view of a plural visual field direction type endoscopeincluding an objective optical system utilizing an eccentric opticalsystem; FIG. 49B is a formation view of an endoscope relating to amodification of the twenty-seventh embodiment;

FIG. 50 is a formation view of an objective optical system in which aneccentric optical system is utilized and an afocal part is partly incommon;

FIG. 51 is a formation view of an objective optical system in which aneccentric optical system is utilized and a perspective is made byrefraction;

FIG. 52 is a formation view of a design of an objective optical systemin which an eccentric optical system is utilized;

FIG. 53 is a formation view of a design in which a relay lens system iscombined with an objective optical system; and

FIG. 54 is an elevation of an objective optical system having threevisual field directions.

FIGS. 55 to 58 relate to the twenty-eighth embodiment, where FIG. 55 isa formation view of a plural visual field direction type endoscopehaving a pupil switching apparatus;

FIGS. 56A and 56B are formation views of a plural visual field directiontype endoscope in which the visual field direction can be switched by animage rotator;

FIG. 57 is a formation view of a plural visual field direction typeendoscope in which the visual field direction can be switched by themovement of a solid state image taking device or the like;

FIG. 58A is a formation view of a plural visual field direction typeendoscope in which a pupil switching apparatus is provided near thepupil of an objective optical system; and

FIG. 58B is a formation view of a plural visual field direction typeendoscope different from that of FIG. 58A.

FIG. 59A is a formation view of a plural visual field direction typeendoscope relating to the twenty-ninth embodiment. FIG. 59B is aformation view of an endoscope in which the objective optical system ismade partly common.

FIG. 60A is a formation view of an optical system of a plural visualfield direction type endoscope of the thirtieth embodiment.

FIG. 60B is a formation view of an optical system of a plural visualfield direction type endoscope of a modification of the thirtiethembodiment.

FIG. 61A is a formation view of an optical system of a plural visualfield direction type endoscope of the thirty-first embodiment.

FIG. 61B is a formation view of an optical system of a plural visualfield direction type endoscope of a modification of the thirty-firstembodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention shall be explained as follows with reference tothe drawings.

The stereoendoscope in each of the first to the twenty-secondembodiments is characterized by having an objective optical system whichhas a plurality of incident pupils formed in different positions andforms a plurality of images having passed through these incident pupilsand having a parallax from each other and a common image transmittingoptical system which transmits the plurality of images having a parallaxfrom each other.

Each of the first embodiment to the modification of the ninth embodimentis of the formation (a). That is to say, images having a parallax fromeach other are formed in separated positions by a plurality of objectiveoptical systems arranged at the distal end of an endoscope and theimages separated from each other are transmitted by one common imagetransmitting optical system.

As shown in FIG. 5, a stereoendoscope apparatus 1 comprises astereoendoscope 2 of the first embodiment having an image taking opticalsystem for stereo-inspection built-in, a light source apparatus 3feeding an illuminating light to an illuminating light transmittingmeans provided in this stereoendoscope to transmit the illuminatinglight, a camera controlling unit (abbreviated as a CCU hereinafter) 4processing signals for an image taking means built-in in thisstereoendoscope 2, a scan converter 5 converting the signal from thisCCU 4 to a video signal, a color monitor 6 displaying the video signalput out of this scan converter 5 and shutter spectacles 27 having ashutter function for stereo-inspecting the image displayed in this colormonitor 6.

The stereoendoscope 2 has an elongate inserted section 11 to be insertedinto a body cavity or the like and a gripped section formed to be largein the diameter at the proximal end of this inserted section so as to begripped by the operator. This inserted section 11 is formed of acylindrical rigid jacket tube made of metal such as stainless steel.That is to say, this stereoendoscope 2 is a rigid endoscope having therigid inserted section 11.

As is an ordinary endoscope, this stereoendoscope has an illuminatinglight transmitting means transmitting the illuminating light fed fromthe light source apparatus 3, an illuminating optical system projectingthis transmitted illuminating light out of an illuminating window andilluminating the object side and an observing optical system obtainingtwo images having a parallax so that the object illuminated by thisilluminating optical system may be stereo-inspected.

By the way, in this specification, this observing optical system ismostly explained in an embodiment acting to form two images having aparallax on an image taking device provided with a photoelectricallyconverting function and is therefore also called an image taking opticalsystem.

The gripped section 12 is provided with a light guide mouthpiece 13 anda light guide connector 15 at the other end of a light guide cable 14removably connected at one end to this light guide mouthpiece 13 isremovably connected to the light source apparatus 3.

A lamp 16 generating a white illuminating light and a lens 17 condensingthis white light are arranged within the light source apparatus 3. Theilluminating light condensed by this lens 17 is radiated on the endsurface of the light guide connector 15, the illuminating light radiatedon this end surface is transmitted by the light guide within the lightguide cable 14 and the transmitted illuminating light is fed to thelight guide 18 side within the stereoendoscope 2 from the light guidemouthpiece 13.

The light guide 18 used as an illuminating light transmitting means isbent within the gripped section 12 and is inserted through the insertedsection 11. This light guide 18 transmits the fed illuminating light andprojects the illuminating light forward from the distal end surfacefixed to the distal end 19 of the inserted section 11 and furtherthrough an illuminating lens 20 fitted to an illuminating window.

The respective optical images (represented by reference numerals 7a and7b in FIG. 6) of the object (represented by the arrow in FIG. 5) 29illuminated by this illuminating light are formed in image formingpositions by objective optical systems 21a and 21b fitted to twoobserving windows arranged adjacently to the illuminating window withinthe distal end 19. The two objective optical systems 21a and 21b are ofthe same formation and are formed of optical lenses preferably of thesame characteristics.

As shown in FIG. 5, the two objective optical systems 21a and 21b havethe respective optical axes Oa and Ob in parallel with the center axisof the inserted section, are arranged substantially superimposed inparallel on both sides of this center axis and are separated from eachother by d in the distance (interval) between both optical axes Oa andOb. Also, both optical axes Oa and Ob are arranged as separated in thediametral direction crossing the center axis and are therefore arrangedsymmetrically with the center axis. Two optical images large in theparallax can be formed by the objective optical systems 21a and 21b ofthe same formation with the optical axes arranged in parallel asseparated by the distance d between them.

The images 7a and 7b are formed, as shown in FIG. 6, in separatepositions by the two objective optical systems 21a and 21b and aretransmitted rearward by a common relay optical system 22, that is, oneimage transmitting optical system or image transmitting means.

These images are both multiple-transmitted rearward by this relayoptical system 22 and finally the same images 10a and 10b as the twoimages 7a and 7b by the two objective optical systems 21a and 21b areseparately formed on a photoelectrically converting surface (imagetaking surface) of an image taking device 23 arranged within the grippedsection 12. For example, in FIG. 5, if the separating direction in thetwo objective optical systems 21a and 21b is a horizontal direction, twoimages 10a and 10b will be separately formed in the horizontal directionon the image taking surface of the image taking device 23.

As shown in FIG. 5, the image taking device 23 has, for example, asquare image taking surface and is arranged so that the vertical orhorizontal direction of this image taking surface may coincide with thehorizontal direction in which the two objective optical systems 21a and21b are arranged as separated and the center of the image taking surfacemay be on the optical axis of the relay optical system.

By the way, the light guide 18 inserted through the inserted section 1may be inserted through outside the relay optical system 22 (forexample, like a ring). As shown in FIG. 5, a part of the verticaldirection intersecting at right angles with the horizontal direction ofthe relay optical system 22 may be contained in an incised groove 422aformed by incising in the axial direction a part of the verticaldirection intersecting at right angles with the horizontal direction ofthe relay optical system 22. (One incised groove 422a is shown in FIG. 5but two incised grooves may be formed in the vertical direction.) Whensuch an incised groove 422a is formed, the part which does not inprinciple substantially contribute to image transmission will bedeleted, the image transmitting function will not be reduced, theilluminating light will be able to be transmitted and the insertedsection 11 will be able to be made small in the diameter.

As the effective sectioned area of the relay optical system can be madelarge, the eccentricity (the distance d between the optical axes) of thetwo objective optical systems 21a and 21b arranged as opposed to eachother eccentrically in the horizontal direction from the optical axis ofthis relay optical system 22 at the front end of this relay opticalsystem 22, that is, the parallax will be able to be made large and thestereo-inspecting function will be able to be improved. Further, thereis a function of reducing the superimposing (cross talk) of two images.

The gripped section can be fittably separated into the output section 24in which the image taking device 23 is built-in and the input section 25on its forward side. The input section 25 has an image taking opticalsystem (observing optical system) comprising the two objective opticalseries 21a and 21b and relay optical system 22.

By making the output section 24 separable, there is made a flexiblestructure wherein the defective image taking device 23 can be easilyrepaired or can be replaced with one high in the sensitivity or thenumber of pixels to improve the performance and an ocular adapter can beconnected to make stereo-inspection with the naked eyes. (The structureshown in the later described FIG. 19 may be adopted for the structure ofthe connecting part.)

The image taking device 23 is extended out of the rear end of the outputsection 24 and is connected with the CCU 4 through the signal cable 26and the image taking signal photoelectrically converted by the imagetaking device 23 is processed. The image signal processed by this CCU 4is further put into the scan converter 5, is converted to a video signaland is then put out to the color monitor 6. Two images corresponding tothe optical images formed by the two objective optical systems 21a and21b are alternately displayed in this color monitor 06. By observing theimages of the color monitor 6 with shutter spectacles 27, the operatorcan stereo-inspect the images.

FIG. 6 shows the formations of the image taking optical systems, thatis, the two objective optical systems 21a and 21b and relay opticalsystem in the stereoendoscope 2 of the first embodiment.

The images 7a and 7b having a parallax from each other are formed by theplurality of (two in this embodiment) independent objective opticalsystems 21a and 21b arranged in the distal end section 19. These images7a and 7b separated from each other are transmitted by the relay opticalsystem 22 as one image transmitting optical system.

As shown in FIG. 6, the objective optical systems 21a and 21b, forexample, the three relay lens systems 22a, 22b and 22c forming the relayoptical system 22 and the image taking device 23 having a function ofphotoelectrically converting optical images are arranged in the ordermentioned from the object side. The two images 7a and 7b having aparallax are formed in the spatially separated positions (in this case,in the positions separated from each other in the horizontal direction)by the objective optical systems 21a and 21b of the same formationarranged in parallel as separated from each other by d (for example, d=4mm) of the distance between their optical axes.

The images 7a and 7b are both multiple-relayed by the relay lens systems22a, 22b and 22c of the same formation arranged in series so that theoptical axes may coincide with each other. That is to say, the images 7aand 7b formed on both left and right sides of the optical axis O of therelay optical system 22 (by the objective optical systems 21a and 21barranged eccentrically on the left and right from this optical axis O)respectively form images 8a and 8b respectively on both right and leftsides of this optical axis O in the rear side positions of the opticalaxis O by the relay lens system 22a. These images 8a and 8b respectivelyform images 9a and 9b on both left and right sides of this optical axisO in the rear side positions of the optical axis O by the relay lenssystem 22b. These images 9a and 9b respectively form images 10a and 10bon both right and left sides of this optical axis O in the rear sidepositions of the optical axis O by the relay lens system 22c.

In this position, the image taking surface of the image taking device 23is arranged and the images 10a and 10b are photoelectrically convertedand put out. A masking means is provided so that the two images 10a and10b on this image taking surface may not be superimposed. (As shown inthe later described FIG. 8, for example, a visual field diaphragm 30 maybe provided on the image forming surfaces of the objective opticalsystems 21a and 21b to limit the visual field. The invention is notlimited to this. The visual field diaphragm may be provided, forexample, in the image forming position in the relay optical system 22.)

The optical axes O of the relay lens systems 22a, 22b and 22c arerespectively eccentric by the same amount on the right and left from theoptical axes Oa and Ob of the objective optical systems 21a and 21b. Theeccentricity can be selected in conformity with the desired parallaxmagnitude, that is, stereo-feel size and is d/2 (for example, d/2=2 mm)in this embodiment.

The number of relaying times is three times in this embodiment but canbe set from one time to ten times and several other times depending onsuch specification as the brightness of the optical system.

By the way, in FIG. 6, the reference numerals 28a and 28b respectivelyrepresent the positions of the incident pupils of the left and rightobjective optical systems 21a and 21b and the left and right images 7aand 7b are formed of the lights incident through the respective incidentpupils 28a and 28b. The respective incident pupils 28a and 28b aretransmitted by the relay lens systems 22a, 22b and 22c forming the relayoptical system 22.

During the transmission by the relay lens systems 22a, 22b and 22c, thetwo pupils may be horizontally displaced but the relay lens systems 22a,22b and 22c had better be superimposed in order to be made small.Therefor, it is preferable that the two objective optical systems 21aand 21b are respectively formed to be telecentric optical systems, thatis, the projecting pupils are formed to be infinitely far.

By the way, the magnitude of the parallax, that is, the center distancebetween the left and right incident pupils 28a and 28b is determined bythe distance d between the optical axes Oa and Ob of the objectiveoptical systems 21a and 21b and is independent of the brightness of theoptical system.

According to this embodiment, as the relay optical system 22 is madecommon, the trouble of adjusting the lenses can be more extremelyomitted than in the case that it is not made common (in the firstrelated art) and a favorable stereo-observation can be made.

Also, as can be judged from FIG. 5, as an image having a parallax can beobtained by arranging the two objective optical systems 21a and 21b asseparated from each other, the parallax can be made larger than in thecase of using a common objective optical system (in the second relatedart) and therefore the function of obtaining a stereo-feel can be madelarge. (The same stereo-feel as in the case that two optical systems arearranged as in the first related art can be obtained.)

Therefore, according to this embodiment, the common optical componentscan be made few, the adjusted parts can be made few, the cost can bemade low and the image having the same stereo-feel as in the case thattwo optical systems are arranged in the related art can be obtained.

As the two images 7a and 7b having a parallax are transmitted by therelay lens systems 22a, 22b and 22c used in common with the axiallysymmetrical one, during the transmission, the qualities (themagnification, MTF, image position, chromatic aberration, coloring andthe like) of the two images will lag little during the transmission.

That is to say, even if the individual characteristics of the relay lenssystem 22a and the others are dispersed by the production error, in thisembodiment, as the left and right images are transmitted by the commonrelay lens system 22a and the others, the influence of the individualdispersion will not be substantially received. Therefore, the left andright images obtained by this embodiment will be images of a goodquality having little lag.

In case an operation is made under the observation with thisstereoendoscope, a good picture quality and a sufficient stereo-feelwill be obtained, a picture image of an observation close to directlyobserving the affected part will be able to be realized and therefore anenvironment in which the operation is easy to make will be able to beprovided.

Also, in this embodiment, as the left and right images 7a and 7b areformed in the positions spatially separated by the objective opticalsystems 21a and 21b and are formed in the positions spatially separatedby the common relay optical system 22, therefore a stereo-inspectionwill be able to be made with the image taking device or the like withoutusing an image separating means newly spatially separating the images.

Also, in this embodiment, the final images 10a and 10b by the relay lenssystem 22c are taken by one image taking device 23. Therefore, theoutput section 24 is very simplified in the structure and a light weightstereoendoscope can be realized.

By the way, the image taking device 23 may be any of various solid stateimage taking devices (known generally by the names of CCD, PCD, CMD, AMIand SIT) and image taking tubes (known generally by the names ofSachicon, Busicon and HARP TUBE).

Also, the sensitivity may be improved by utilizing an image intensifieror the like.

The image taking device 23 may be a device for taking color images witha single plate or may take colored images with a formation as a 2-plateor 3-plate camera. Also, as shown in FIG. 6, the final images 10a and10b by the relay lens system 22c are taken by the common image takingdevice 23 to reduce cost and weight.

In order that a stereo-feel optimum to the desire or operation type ofthe operator may be obtained, the distance between the respectiveoptical axes of the two objective optical systems 21a and 21b may bemade variable so that the magnitude of the parallax may be variable.

In this case, in order that the distal end section 19 may be made small,the two objective optical systems 21a and 21b may be made movable to theside opposite to one another in the horizontal direction vertical to theoptical axis O of the relay lens systems 22a, 22b and 22c. However, inthis case, when the objective optical systems 21a and 21b move, thefinal images 10a and 10b will be also moved by the relay lens system 22cand therefore, in case the image taking device 23 is fixed, the movementwill be limited to be within the image taking range.

By the way, it has been explained that the image taking surface of theimage taking device 23 is square. However, a rectangular surface havinga long horizontal direction in which the objective optical systems 21aand 21b are arranged as separated may be used. In this case, the imagetaking range in which the image having a parallax is obtained will beable to be substantially expanded.

By the way, FIG. 5 shows a simultaneous illuminating and image takingsystem wherein a color image is taken by using the image taking device23 in which such color separating filter as a mosaic filter is arrangedunder a white color light illumination. However, the invention is notlimited to this. A surface sequential image taking system wherein acolor image is taken by obtaining such color component image as of threeprimary colors by taking an image with an image taking device having nocolor separating filter under a surface sequential illumination in whichilluminating lights of such wavelength ranges as of red, green and blueare sequentially emitted on the object side will also do.

By the way, in the first embodiment, instead of connecting the outputsection to the input section 25, an ocular adapter 45' shown in thelater described FIG. 16D is fitted so that the stereo-inspection may bemade with the naked eyes. In this case, it is preferable to set thenumber of relaying times by the relay optical system 22 at an evennumber of times so that the left and right images 7a and 7b by theobjective optical systems 21a and 21b may be respectively observed withthe left and right ocular lenses. (In FIG. 16D, the number of relayingtimes is four times.)

By the way, the lens data of the first embodiment are as in Table 1shown later in the specification. FIG. 2 and others are collectivelyshown after FIG. 1. In Tables 1 to 14, r1, r2, . . . , represent radiiof curvatures of respective surfaces, d1, d2, . . . , represent surfacedistances, n1, n2, . . . , represent refractive indices of respectivelenses and ν1, ν2, . . . , represent Abbe numbers of respective lenses.

In the following, the second to ninth embodiments are modifications ofthe first embodiment and, the same as in the first embodiment, the imagehaving a parallax is formed in a position spatially separated by theobjective optical systems 21a and 21b.

FIG. 7 shows a structure near the final images 10a and 10b of the relaylens system 22c of the image taking optical system in thestereoendoscope of the second embodiment of the present invention. Thefinal images 10a and 10b are respectively taken by the two image takingdevices 23a and 23b. Signal lines (not illustrated) are connectedrespectively to the two image taking devices 23a and 23b and areconnected to a CCU partly different in the internal formation from theCCU 4 in FIG. 5. The others are of the same formation as of thestereoendoscope 2 of the first embodiment.

By the way, in the CCU processing signals for the two image takingdevices 23a and 23b, the same driving signal may be simultaneouslyapplied, for example, to the two image taking devices 23a and 23b, maybe simultaneously read out and may be memorized respectively in twoframe memories. The same driving signal may be applied alternatelyrespectively to the two image taking devices 23a and 23b and may be readout alternately and the image signal read out may be memorizedalternately in the two frame memories.

The image signal simultaneously or alternately memorized in the twoframe memories are alternately read out by the scan converter and arealternately displayed in the color monitor. The operator wears shutterspectacles 27 and can observe and stereo-inspect the image displayed inthe color monitor 6.

The stereoendoscope apparatus provided with this second embodiment canbe realized in substantially the same formation as of thestereoendoscope apparatus 1 in FIG. 5.

This second embodiment has an advantage that the image taking devices23a and 23b can be focused respectively independently. If they areprecisely adjusted, an image higher in the quality than in the case of acommon image taking device 23 will be able to be made.

Also, the parallax can be made variable the same as in the firstembodiment. However, this embodiment has an advantage that, when theleft and right image taking devices 23a and 23b are moved as operativelyconnected with the movement of the objective optical systems 21a and21b, the movement will not be restricted to be within the image takingrange in the case of the common image taking device 23.

That is to say, in the first embodiment, as the image taking device 23is common, the moving range of the left and right images 10a and 10b isrestricted to be within the image taking range. However, according tothe present embodiment, in case the final images 10a and 10b are fixed,when the movement deviates (separates) from the imaging range, the twoimage taking devices 23a and 23b will be moved horizontally asoperatively connected with the movement of the objective optical systems21a and 21b and the final images 10a and 10b will be able to bemaintained within the image taking range of the respective image takingdevices 23a and 23b.

Therefore, there is a merit that a stereo-endoscope in which an imagehaving a stereo-feel is obtained can be realized. The others have thesame effects as in the first embodiment. By the way, the lens data ofthe second embodiment are the same as of the first embodiment.

FIGS. 8 and 9 relate to the third embodiment of the present invention.FIG. 8 shows an image taking optical system in the third embodiment.FIG. 9 shows as magnified the arrangement of the image taking devices23a and 23b. In this embodiment, the two image taking devices 23a and23b are used as in the second embodiment and the light receivingsurfaces of the image taking devices 23a and 23b arranged not verticallyto the optical axis O of the relay optical system 22 but as inclinedfrom the vertical direction. In other words, in the central part of thelight receiving surface of each of the image taking devices 23a and 23b,the optical axis vertical to this light receiving surface is arrangednot to be parallel with the optical axis O of the relay optical system22 but to make an angle greater than 0.

That is to say, when the light receiving surface of each of the twoimage taking devices 23a and 23b is inclined in conformity with theimage surface curvature aberration 10c generated by the relay lenssystems 22a, 22b and 22c and shown in FIG. 9, the deterioration of theimage by the curvature aberration will be reduced.

As the petzval of the relay lens systems 22a, 22b and 22c is positive,even if the image surface by the objective optical systems 21a and 21bis flat, in the case of the transmission by the relay lens systems 22a,22b and 22c, the image surface will bend on the curved surface with theconcave surface directed to the objective side.

Therefore, with the image taking surface or light receiving surface leftto be arranged vertically to the optical axis of the relay lens systems22a, 22b and 22c, a partial fog will likely be produced and it will bedifficult to keep the entire image taking surface focused.

Therefore, in the third embodiment, as shown in FIG. 9, the lightreceiving surface is inclined in conformity with the contact surface ofthe curved image surface. In FIG. 9, the light receiving surface isinclined by 25.332 degrees to the surface vertical to the optical axisof the relay lens system 22c.

According to this third embodiment, not only the effects of the secondembodiment are retained but also a picture image having little curvatureaberration is obtained. By the way, the lens data of the thirdembodiment are as in Table 2.

By the way, because the petzval sum of the relay lens systems 22a, 22band 22c is a positive value, the petzval sum of the objective opticalsystems 21a and 21b may be made a negative value to control the imagesurface curvature aberration of the final images 10a and 10b havingpassed through the relay lens system 22c.

FIGS. 10A and 10B are of modifications showing this manner.

As shown in FIG. 10A, the petzval sum of the objective optical systems21a and 21b is made a negative value to form images 7a and 7b becomingconcave on the rear side (the local radius of curvature of each imagesurface shall be represented by R). In case the image on the flat imagesurface is transmitted by the relay lens systems 22a, 22b and 22c, thelocal radius of curvature of the image surface of the final images 23aand 23b is represented by R' and, as shown in FIG. 10, the lightreceiving surfaces of the image taking devices 23a and 23b are arrangedon the contact surface of the curved surface of a local curvature1/R"=1/R -1/R", the influence of the image surface curvature aberrationwill be further controlled by this embodiment than by the thirdembodiment.

By the way, in this case, 1/R -1/R"=0 or the absolute value of 1/R -1/R"may be made small.

FIG. 11 shows an image taking optical system in the fourth embodiment.The final images 10a and 10b of the relay lens system are relayed oncemore by adapter lens systems 32a and 32b forming an adapter opticalsystem to connect images 36a and 36b and these images 36a and 36b aretaken respectively by image taking devices 33a and 33b.

The adapter lens systems 32a and 32b are formed respectively of mirrorparts 34a and 34b and lens parts 35a and 35b, a beam is parallel movedoutside by the mirror parts 34a and 34b (in this embodiment, thedisplacement L is 6 mm) and the lens parts 35a and 35b act to re-formthe final images 10a and 10b of the relay lens system at anymagnification.

The optical axis of each of the lens parts 35a and 35b is eccentric byd/2 (2 mm) from the optical axis of the relay lens system 22c except theparallel moved part by the mirror parts 34a and 34b.

In this embodiment, when the parallel moving distance in the mirrorsections 34a and 34b and the magnification in the lens sections 35a and35b are properly set, images 36a and 36b optimum to any size imagetaking devices 33a and 33b will be able to be obtained.

Also, as the image taking devices 33a and 33b larger in the size than inthe first and second embodiments can be used, those larger in the numberof pixels in response to the size can be used and a favorablestereo-observed image high in the resolving degree can be obtained. Theothers have the same effects as in the second embodiment. The lens dataof this embodiment are as in Table 3.

FIG. 12 shows an image taking optical system in the fifth embodiment.This embodiment is an improvement of the fourth embodiment.

The images 36a and 36b are respectively formed by further relaying oncethe final images boa and 10b of the relay lens system with the commonadapter optical system 32 formed of one lens system and are taken by theimage taking devices 33a and 33b. The adapter optical system 32 isformed of a lens system arranged so as to be of the same optical axis asof the relay lens systems 22a, 22b and 22c, the final images 10a and 10bof the relay lens system are formed again at any magnification and theimage taking devices 33a and 33b are arranged in the image formingpositions.

In this embodiment, the formation can be made simpler by the part havingno mirror section within the adapter optical system 32 and has theoperations and effects of the fourth embodiment. That is to say, whenthe magnification of the adapter optical system 32 is optionally set,the images 36a and 36b optimum to the image taking devices 33a and 33bof any size will be able to be obtained.

Also, in this embodiment, the same as in the third embodiment, the lightreceiving surface of each of the image taking devices 33a and 33b isinclined in conformity with the image surface curvature aberrationgenerated by the relay lens systems 22a, 22b and 22c and adapter opticalsystem 32 to control the deterioration of the image. In FIG. 12, thelight receiving surface is inclined by 11.902 degrees to the surfacevertical to the optical axis of the relay lens system 22c. The lens dataof this embodiment are shown in Table 4.

FIG. 13 shows an image taking optical system in the sixth embodiment.

The final images 10a and 10b of the relay lens system are further oncerelayed by the adapter lens systems 32a and 32b forming the adapteroptical system 32 and are taken by the image taking devices 33a and 33b.The adapter optical system 32 is formed of the two inclined adapter lenssystems 32a and 32b of the same formation. One lens system 32b and theimage taking device 33b are parallel eccentric by d/2 (=2 mm) from theoptical axis of the relay lens system 22c and are then inclined by10.076 degrees with the point at which the optical axis of the lenssystem 32b intersects with the final image 10b of the relay lens system22c as a center. The lens system 32a illustrated by the two-point chainlines is also inclined the same on the opposite side of the optical axisof the relay lens system 22c.

In this embodiment, too, the same as in the fifth embodiment, no mirrorsection is present and, by freely setting the magnification of theadapter optical system, the images 36a and 36b optimum to the imagetaking device of any size can be obtained. That is to say, thisembodiment has substantially the same effects as in the fifthembodiment. The lens data of this embodiment are as in Table 5.

FIG. 14 shows a main part of an image taking optical system in theseventh embodiment of the present invention.

The final images 10a and 10b of the relay lens system are further oncerelayed by the adapter optical system 32 and are formed in the samepositions and the common image taking device 33 is arranged in the imageforming position in the formation.

In the adapter optical system 32, the final images 10a and 10b of therelay lens system are led to the shutter means 37e side through anoptical axis distance extending means comprising respectively lenses 37aand 37b and prisms 37c and 37d and are led to the opposed lens 37f and37g side so that, when one is shielding light, the other will be passinglight. A beam having passed through the lens 37f arranged as opposed toone side of the shutter means 37e passes through the prism 37h, halfprism 37i and lens 37j and forms an image 36a in the position in whichthe image taking device 33 is arranged.

Also, a beam having passed through the lens 37g arranged as opposed tothe other side of the shutter means 27e passes through the opticaldevice 37k, half prism 37i and lens 37j and forms an image 36b in theposition in which the image taking device 33 is arranged.

In this embodiment, the relayed images 36a and 36b are formed in thesame position and are taken by one image taking device 33. The shuttermeans 37e is arranged on the way of the adapter optical system 32 andalternately shields the beam so that two images may not besimultaneously formed by the image taking device 33.

This embodiment has an advantage that one image taking device 33 will doand the cost can be reduced. The others have the same effects as of thefourth embodiment.

FIGS. 15A and 15B show a formation of an objective optical system in theeighth embodiment of the present invention.

In this embodiment, an objective optical system is formed of perspectiveobjective optical systems 39a and 39b having a perspective front as avisual field.

In this embodiment, a beam incident from the diagonal front side isreflected by using reflecting prisms 40a and 40b as visual fielddirection changing means and is changed to be in a direction parallel tothe optical axis O of the relay optical system 22 (FIGS. 15A and 15Bshow only a part of the relay lens system 22a). In this embodiment, thevisual field direction is 45 degrees with the lengthwise direction (theoptical axis direction of the relay optical system 22) of the insertedsection. The reflecting prisms 40a and 40b may be two separate bodies orone integral body.

The rear side formation of the relay optical system 22 may be theformation of any of the first to sixth embodiments. This embodiment hasthe same effects as in the first to seventh embodiments except that thevisual field direction is different.

Other than the eighth embodiment, the visual field direction can bevaried by varying the angles of the reflecting prisms 40a and 40b. Also,if the objective optical system parts are replaceably formed, variousvisual field directions, visual field angles and parallaxes will be ableto be obtained by replacing only the objective optical system.

FIGS. 16A to 16D show the ninth embodiment of the present invention anda unit formation in its first modification.

The stereoendoscope 41 of the ninth embodiment shown in FIG. 16Acomprises an objective optical system unit 42, relay optical system unit43, adapter optical system unit 44 and image taking device unit 45.

The objective optical system unit 42 has objective optical systems 21aand 21b of uniform optical characteristics built-in. The relay opticalsystem unit 43 has relay lens systems 22a, 22b, 22c and 22d of the sameformation built-in. The adapter optical system unit 45 has a commonadapter optical system 32 built-in. The image taking device unit 45 hasimage taking devices 33a and 33b of uniform characteristics built-in.

FIG. 16A as seen from the side is as in FIG. 16B. The objective opticalsystem unit 42 has a distal end side section of a light guide 18 and anilluminating lens 20 built-in. The relay optical system unit 43 has anintermediate section of the light guide 18 built-in. The adapter opticalsystem unit 44 has a rear end side section of the light guide 18built-in. A light guide mouthpiece 13 is provided.

Also, in this embodiment, the relay lens systems 22a, 22b, 22c and 22dwithin the relay optical unit 43, for example, (for example, are cut offin the lengthwise direction on the lower side to be in the directionvertical to the horizontal direction in which the objective opticalsystems 21a and 21b are arranged to secure a space to contain the lightguide 18 and) make the inserted section small in diameter. Also, theadapter optical system 32 within the adapter optical system unit 44 iscut off on the light guide mouthpiece 13 side.

In this embodiment, the objective optical system unit 42 is connected tothe distal end of the relay optical system unit 43, the distal end ofthe adapter optical system unit 44 is connected to the proximal end ofthe relay optical system unit 43 and the image taking device unit 45 isconnected to the proximal end of this adapter optical system unit 44 toform a stereoendoscope 41.

Therefore, by combining the respective units different in the opticalcharacteristics and image taking characteristics, stereoendoscopes ofdifferent characteristics can be simply realized. Therefore, thestereoendoscopes 41 of different characteristics can be provided.

In this embodiment, the connecting part of the proximal end of the relayoptical system unit 43 and the distal end of the adapter optical systemunit 44 corresponds to the border of the input section 25 and outputsection 24 shown in FIG. 5.

By the way, in FIGS. 16A and 16B, the part after the adapter opticalsystem unit 44 is made large in diameter. However, as shown in FIG. 16C,the proximal end side of the relay optical system unit 43 may be madelarge in the diameter on the proximal end side, the proximal end sidepart of the light guide 18 may be built-in near this proximal end andthe light guide mouth piece 13 may be provided there in the structure.

In this first modification, the light guide 18 need not be built-in inthe adapter optical unit 44 and therefore the structure will be simple.

In this modification, the image taking device unit 45 may be fitteddirectly to the relay optical system unit 43 without using the adapteroptical system unit 44 in the structure. In such a case, the formationof the second embodiment will be made. Further, in case one common imagetaking device is built-in as the image taking device unit 45, theformation of the first embodiment will be made.

This first modification is higher in the freedom of combination than theninth embodiment and can simply realize stereoendoscopes 41 different inthe characteristics. Also, as shown in FIG. 16D, when an ocular adapter45' is connected to the proximal end of the relay optical system unit43, a stereoendoscope by which stereo-inspection can be made with thenaked eyes will be able to be formed.

The ocular adapter 45' shown in FIG. 16D has a structure whereby thefinal images by the relay optical system unit 43 can be magnified andobserved respectively through prisms and ocular lenses 45"a and 45"bfitted to an ocular window corresponding to the distance between botheyes of the operator so that the left and right images by the objectiveoptical systems 21a and 21b may be respectively stereo-inspected throughthe left and right ocular lenses 45"a and 45"b.

By the way, in this case, because the final images are inverted images,the ocular adapter 45' is provided with lenses 45'a and 45'b as meansfor making them upright to form upright images in front of the ocularlenses 45"a and 45"b. Instead of providing the lenses 45'a and 45'b, thetwo prisms for extending the distance between the optical axes mayconsist of prisms for inverting images such as Porro prisms.

The ocular adapter for observation with the naked eye may be connectableto the relay optical system unit 43 in FIG. 16A in the structure or maybe connectable to the second to fourth modifications of the ninthembodiment shown in FIGS. 17A to 17C explained in the following.

In the second modification shown in FIG. 17A, in FIG. 16A, the adapteroptical system 32 and the image taking devices 33a and 33b are formed ofan adapter optical system image taking unit 46 as one unit.

In the third modification shown in FIG. 17B, in FIG. 17A, further, theobjective optical systems 21a and 21b and the relay optical system 22are formed of an objective optical system relay optical system unit 47as one unit. In the fourth modification shown in FIG. 17C, in FIG. 16A,the relay optical systems 22 and the adapter optical system 32 areformed of a relay optical system adapter optical system unit 48 as oneunit.

FIGS. 18A to 18E show more actual formations of various units used inthe ninth embodiment and its modifications.

FIG. 18A shows an objective optical system unit 42 of a visual fieldangle of 70 degrees. FIG. 18B shows an objective optical system unit 42of a visual field angle of 40 degrees. When they are replaced and areconnected to a relay optical system unit 43, any desired visual fieldangle will be obtained.

A male screw is formed at the proximal end of the jacket tube of theobjective optical system unit 42 and can be removably connected by beingscrewed to a female screw at the distal end of the jacket tube of therelay optical system unit 43. A projection is provided at the proximalend of the jacket tube of the objective optical system unit 43 and canbe contacted with a level difference surface made by cutting off theinner peripheral surface on the distal end side of the jacket tube ofthe relay optical system unit 43 to determine the position in thelengthwise direction. By the way, both jacket tubes have the sameoutside diameter so that, in case they are connected with each other, nolevel difference will be made on the inserted section.

Also, a positioning mark and screw hole are provided as peripheralpositioning means near the proximal end of the jacket tube of theobjective optical system unit 42. When this mark is made to meet apositioning mark at the distal end of the jacket tube of the relayoptical system unit 43, both screw holes will be able to be set tocommunicate with each other and will be able to be fixed with a screw(not illustrated).

By the way, the same connecting means or connecting mechanism as on theproximal end side of the jacket tube of the objective optical systemunit 42 is provided on the proximal end side of the jacket tube of therelay optical system unit 43 and can be removably connected to thedistal end of the jacket tube of the adapter optical system unit 44.

FIG. 18C shows an objective optical system unit 42 perspective in thevisual field direction of 45 degrees. In FIG. 18C, by replacing thereflecting prism 40, the objective optical system unit 42 perspective inany visual field direction can be formed. By the way, FIG. 18D showsFIG. 18C as seen from the rear end side and a pair of objective opticalsystems 39a and 39b arranged on the left and right.

FIG. 18E shows an objective optical system 42 in which the parallax isreduced and the optical axes of two objective optical systems 21a and21b are near each other and the distance d' between the optical axes isd'<d. In this formation, the stereo-feeling will be reduced but, as theobjective optical systems are arranged on the center axis side, a spacefor inserting them through other internal organs or the like will beable to be secured, therefore, for example, the cross-sectioned area ofthe light guide will be able to be made large, the illuminating lightamount will be able to be increased and a bright image will be obtained.

By the way, when the image taking device unit or the adapter opticalsystem unit is replaced, as required, in response to the optical axisdistance and visual field angle of the objective optical systems 21a and21b, an optimum stereoendoscope conforming to the equivalent will beable to be provided.

FIG. 19A shows a formation of a relay optical system unit 43. Theproximal end of this relay optical system 43 can be removably connectedto the distal end of the adapter optical system unit 44. Also, theproximal end of this adapter optical system unit 44 can be removablyconnected to the image taking unit 45.

As shown, for example, in FIG. 19B, the relay optical system unit may bethe relay optical system unit 43 in which the number of relaying timesis doubled. Further, a relay optical system unit in which the number ofrelaying times is different depending on the length inserted into thebody cavity or the like can be also used.

FIG. 19C shows a formation of an objective optical system relay opticalsystem unit 47 for integrating an objective optical system and a relayoptical system. FIG. 19D is a modification of FIG. 19C and shows a unitin which the number of relaying times of the relay optical system isdoubled. Various numbers of relaying times of the relay optical systemcan be prepared. A different length of the inserted section can beselected as required.

In the following, the tenth to eighteenth embodiments are embodiments ofthe formation (b) in the above mentioned paragraph of the summary.Images having a parallax with each other are taken into the plurality offront group optical systems of the objective optical systems arranged inthe distal end section of the endoscope and a plurality of images in onerear group optical system are formed in substantially coincidingpositions. These substantially superimposed images are transmitted by acommon rear group optical system and a common image transmitting systemcoinciding with this rear group optical system in the optical axis. FIG.20 shows an image taking optical system in the tenth embodiment.

An objective optical system 51 in which the object side opening part isseparated into two parts, relay lens systems 52a, 52b and 52c, anadapter optical system 50 and image taking devices 53a and 53b arearranged in the order mentioned from the object side. The objectiveoptical system 51 is formed of front group optical systems (abbreviatedmerely as front groups) 54a and 54b of the same formation which arearranged parallel as separated by the distance d (=4 mm) between theoptical axes of each other and a rear group optical system (abbreviatedmerely as a rear group) 55 arranged to be of one same optical axis. Twoimages 56a and 56b having a parallax are formed in spatiallysubstantially coinciding positions.

The images 56a and 56b form a relay optical system and are equallymultiple-relayed by (for example, three) relay lens systems 52a, 52b and52c of the same formation arranged in series so as to have the sameoptical axis.

That is to say, by the relay lens system 52a, the images 56a and 56bform images 57a and 57b with equal sizes in substantially the samepositions in the rear of this relay lens system 52a. By the relay lenssystem 52b, these images 57a and 57b form images 58a and 58b with equalsizes in substantially the same positions in the rear of this relay lenssystem 52b. By the relay lens system 52c, these images 58a and 58b formimages 59a and 59b with equal sizes in substantially the same positionsin the rear of this relay lens system 52c.

The rear group 55 of the objective optical system 51 and the opticalaxis of the relay lens systems 52a, 52b and 52c are on the same axis.This optical axis and the optical axis of the front groups 54a and 54bare respectively eccentric on the left and right.

The eccentricity can be selected in conformity with a desired size, thatis, the size of the stereo-feel and is respectively d/2 (=2 mm) in thisembodiment. An afocal beam may not be between the front groups 54a and54b and the rear group 55. However, this part may be of an afocal beam.An image formed by the objective optical system should be substantiallysuperimposed.

For the picture angle of the ordinary relay system, the picture anglerequired by the endoscope is large. Because, as described above, thefront groups 54a and 54b must be nearly afocal and because there must befew parts not in common, the front groups 54a and 54b must be formed ofa concave group and a convex group from the object side.

When the plurality of images having a parallax and which are transmittedby the relay optical system are substantially superimposed, the relayoptical system will be able to be made small in the diameter. Therefore,the projected pupil of the objective optical system 51 may be madesubstantially infinite. Therefore, the front side focal position of therear group 55 of the objective optical system 51 will be the pupilposition. So that the beam entering the front groups 54a and 54b fromthe object may be well transmitted to the rear group 55, it ispreferable to the projected pupil of the front groups 54a and 54bcoincide. It is preferable that the final surfaces of the front groups54a and 54b are arranged on the image side rather than in the front sidefocal position of the rear group 55.

In this embodiment, there are three relaying times which can be selectedand set to be usually one time to ten or more times depending on suchspecifications as the length and diameter of the inserted section of theendoscope and the brightness of the optical system.

The magnitude of the parallax, that is, the center distance between theright and left incident pupils, is determined by the optical axisdistance d between the front groups 54a and 54b of the objective opticalsystem 51 and is independent of the brightness of the optical system.

According to this embodiment, the same as in the first embodiment, thetwo images 56a and 56b having a parallax are transmitted by one axiallysymmetrical relay optical system and therefore little error will begenerated in the various optical qualities (the magnification, MTF,image position, chromatic aberration, coloring and the like) of the twoimages being transmitted.

There are fewer non-common parts on the right and left of the objectiveoptical system 51 than in the first embodiment. Therefore, theadjustment of lenses proves not to be troublesome and a favorablestereo-observed image can be obtained.

Further, in this embodiment, as spatially substantially superimposedimages are transmitted by the relay optical system, when each of thefront groups 54a and 54b is formed of an elliptic lens system in which,for example, the horizontal direction is a short axis and the verticaldirection is a long axis and the pupil is also made elliptic, theobjective optical system and relay optical system will be able to bemade small in diameter without deteriorating the parallax, brightnessand the like. In this case, the inserted section will be able to be madesmall in diameter from the distal end to the proximal end side and theapplied range in which the endoscope can be inserted and used will beable to be expanded. Because the hole through which the inserted sectionis inserted into the abdominal part can be made small, the patient willexperience a reduction in pain. By the way, even in the otherembodiments, the objective optical system may be formed of an ellipticlens system.

In this embodiment, the final images 59a and 59b of the relay lenssystem 52c are in substantially the same position and therefore must beseparated from each other by any means which is a pupil dividing imageforming means.

Therefor a means for forming an image of a pupil transmitted by therelay optical system and a means for forming an image of a partial beamof this pupil and forming an image by spatially separating plural imageshaving a parallax are required. The adapter optical system 50 formed ofthe pupil image forming lens system 61, mirror parts 62a and 62b andimage forming lens systems 63a and 63b arranged to be on the sameoptical axis as of the relay lens system 52c perform these functions.

The pupil image forming lens system 61 forms in spatially separatedpositions images of two pupils of the objective optical system 51transmitted by the relay lens systems 52a, 52b and 52c. In the mirrorparts 62a and 62b, the beams of the two pupils are moved outside (inthis embodiment, the movement is 6 mm) in parallel and the image forminglens systems 63a and 63b form images 64a and 64b respectively in theimage taking devices 53a and 53b.

The optical axes of the image forming lens systems 63a and 63b areeccentric by d/2 (=2 mm) from the optical axis of the relay lens system52c, except for the part moved in parallel by the mirror parts 62a and62b. By the way, the mirror parts 62a and 62b and image forming lenssystems 63a and 63b are illustrated respectively only on one side.

Lest the right and left pupils should be finally superimposed, abrightness diaphragm 79 may be provided on the pupil surface (in thisembodiment, on the projecting pupil surface of the pupil image forminglens) in any of the pupil position and its conjugate position to limitthe beam.

In this embodiment, when the parallel moving distance in the mirrorparts 62a and 62b and the magnification of the adapter optical system 50are properly set, the images 64a and 64b optimum to the image takingdevices 53a and 53b of any size will be able to be obtained.

As in FIG. 20, the parallel moving direction of the mirror parts 62a and62b may be any direction within or vertical to a plan containing thepaper surface. When the focal distances of the image forming lenssystems 63a and 63b are varied, the magnification will be able to bealso varied.

In order to obtain the stereo-feel optimum to the operator's desire or asystem, the optical axis distances between each other of the two frontgroups 54a and 54b may be made variable so that the magnitude of theparallax may be variable. In this case, in order to make the distal endsection small, the two front groups 54a and 54b may be made movable inthe directions reverse to each other vertically to the optical axis ofthe relay optical system.

However, in this case, because the projected pupil of the objectiveoptical system is moved by the movement of the front groups 54a and 54b,it will be necessary to make the effective diameter of each lens ratherlarge so that the beam may not be intercepted by the optical systemsfollowing the relay lens systems 52a, 52b and 52c.

The other operations and effects are the same as in the firstembodiment. The lens data of this embodiment are shown in Table 6.

The following eleventh to seventeenth embodiments are made by modifyingthe formations of the tenth embodiment. The images having a parallaxbetween each other are formed in spatially substantially coincidingpositions. All these objective optical systems 51 can be formed to beinterchangeable with the objective lenses of the pupil dividing typestereoendoscope of the related art.

FIG. 21 shows an image taking optical system in the eleventh embodimentof the present invention. Images 64a and 64b are formed by further oncerelaying the final images 59a and 59b of the relay lens system with theadapter optical system 50 and are taken by the image taking devices 53aand 53b.

The adapter optical system 50 is formed of a pupil image forming lenssystem 61 and image forming lens systems 63a and 63b arranged to be ofthe same optical axis as of the relay lens system 52c. The optical axesof the image forming lens systems 63a and 63b are eccentric by 1.25d (=5mm) from the optical axis of the relay lens system 22c.

By the way, the image forming lens system is illustrated only on oneside. This embodiment is simpler than the tenth embodiment because thereis no mirror part within the adapter optical system 50. As in the tenthembodiment, when the magnification of the adapter optical system 50 isfreely set, the images 64a and 64b optimum to any image taking devicewill be able to be obtained. The distance between the two pupils dividedby the pupil image forming lens system 61 can be varied by adjusting thefocal distance of this pupil image forming lens system 61. The otheroperations and effects are the same as the tenth embodiment.

The lens data of this embodiment are shown in Table 7.

FIG. 22 shows an image taking optical system in the twelfth embodimentof the present invention. The front groups 54a and 54b of the objectiveoptical system 51 are formed of meniscus lenses 65a and 65b having aconcave surface on the object side. In this embodiment, because thereare fewer non-common parts of the right and left light paths than in theeleventh embodiment, the error between the qualities of the two imageswill be less.

The lens data of this embodiment are shown in Table 8.

Further, when the meniscus lenses 65a and 65b are constructed as anintegrally molded lens 65 as shown in FIGS. 23A to 23D, the error on theright and left from the objective optical system 51 to the pupil imageforming lens system 61 will be able to be reduced to a level where theerror will not be a practical problem and the trouble of adjusting thelenses will be well eliminated. The other operations and effects are thesame as in the eleventh embodiment.

By the way, of FIGS. 23A to 23D, FIG. 23A is a sectioned plan view, FIG.23B is a side view of FIG. 23A as seen in the side direction and FIGS.23C and 23D are a front view and back view, respectively, as seem fromthe front side and back side.

FIG. 24 shows an image taking optical system in the thirteenthembodiment of the present invention. The final images 59a and 59b of therelay lens system are further once relayed by the adapter optical system50. Because the adapter optical system 50 is of the same optical axis asof the relay lens system 52c, the relayed images 64a and 64b will beformed in substantially the same positions and will be taken by onecommon image taking device 53.

A shutter 66 is arranged between the pupil image forming lens system 61and image forming lens system 63 and alternately intercept the beam sothat two images may not be simultaneously formed in the image takingdevice 53.

This embodiment has an advantage in that only one image taking device 53is required. The other effects are the same as in the twelfthembodiment.

The lens data of this embodiment are shown in Table 9.

FIG. 25 shows a main part of an image taking optical system in thefourteenth embodiment of the present invention. As in the thirteenthembodiment, because the adapter optical system 50 has the same opticalaxis as that of the relay lens system 52c, the relayed images 64a and64b will be formed in substantially the same positions and will be takenby one image taking device 53.

A lenticular lens 67 is arranged just before the light receiving surfaceof this image taking device 53 which is commonly used. When the rightand left images are formed at intervals of one row or one line by theimage taking device 53, the two images will be separately taken. Thisembodiment has also an advantage in that only one image taking device 53is required. The other effects are the same as in the thirteenthembodiment. By the way, the lens data of this embodiment are the same asin the thirteenth embodiment.

FIGS. 26A and 26B show an objective optical system in the fifteenthembodiment of the present invention. In this embodiment, the visualfield direction is 30 degrees with the lengthwise direction of theendoscope (the optical axis direction of the relay lens). The reflectingprisms 68a, 68b and 69a, 69b forming the front groups 54a and 54b may berespectively two separate bodies or one integral body.

FIG. 27 shows an objective optical system in a modification of thefifteenth embodiment of the present invention. As in the fifteenthembodiment, a perspective objective optical system 70 is formed. In thismodification, the visual field direction is 70 degrees with thelengthwise direction of the endoscope (the optical axis direction of therelay lens). The reflecting prisms 68a, 68b and 69a, 69b may berespectively two separate bodies or one integral body.

In the fifteenth embodiment and its modification, the visual fielddirection can be varied by varying the angles of the reflecting prisms68a, 68b and 69a, 69b. Therefore, when the front group part is formed tobe interchangeable, various visual field directions or visual fieldangles will be able to be obtained by interchanging only this frontgroup. Needless to say, even when the entire objective optical system isformed to be interchangeable, the same effects will be obtained. Theother effects are the same as in the tenth embodiment.

FIG. 28 shows an image taking optical system in the sixteenth embodimentof the present invention. As in the fifteenth embodiment, in thisembodiment, the perspective objective optical system 70 is used. In thisembodiment, the visual field direction is 45 degrees with the lengthwisedirection of the endoscope (the optical axis direction of the relaylens). The reflecting prism 71 is integral on the right and left.

That is to say, in the illustrated tenth to fifteenth embodiments, theoptical system divided into two parts of the front groups 54a and 54b isadopted. However, in this embodiment, a common reflecting prism 71 isused to form a front group 54 functioning the same as the two separatedfront groups 54a and 54b.

Negative lens systems 72a and 72b, such as negative power elements, andpositive lens systems 73a and 73b, such as positive power elementsforming the front group 54 on the left and right are formed in pairs asarranged eccentrically respectively on the left and right and arerotatable as illustrated. Therefore, the arranging direction of the twoincident pupils of the objective optical system, that is, the directionof the parallax (the direction of d in FIG. 28) can be varied and it isvery effective in permitting stereo-observing of an object in manydirections.

In this embodiment, with the rotation of the negative lens systems 72aand 72b and positive lens systems 73a and 73b, the incident pupil of thepupil image forming lens system 61 will also rotate. In the embodimentshown in FIG. 28, the adapter optical system 50 shows an example in casethe same formation as of the eleventh embodiment is adopted. The imageforming lens systems 63a and 63b and the image taking devices 53a and53b will synchronously rotate to prevent the beam from beingintercepted.

Even in this embodiment, when the angle of the reflecting prism 71 isvaried; the visual field direction will be able to be varied, when thecombination of the focal distances of the negative lens and positivelens is varied, the visual field angle will be able to be varied; andwhen the optical axis distance between the negative lens and positivelens on the left and right is varied, the magnitude of the parallax willbe able to be varied.

This embodiment can be applied to another adapter optical system.However, as mentioned above, with the rotation of the negative lenssystems 72a and 72b and positive lens systems 73a and 73b, the projectedpupil of the pupil image forming lens system 61 will also rotate.Therefore, it is necessary to rotate such parts having left and rightseparate optical axes as, for example, the mirror parts 62a and 62b,image forming lens systems 63a and 63b, image taking devices 53a and 53band the like as synchronized in the tenth embodiment in FIG. 20. Theother effects are the same as of the tenth embodiment.

FIG. 29 shows the seventeenth embodiment of the present inventionwherein the front group 54 including the negative lens systems 72a and72b and positive lens systems 73a and 73b is arranged on the object sideof the reflecting prism 71.

In this embodiment, as the rotating parts in the front group 54 part canbe concentrated in one place (in this case, on the object side of thereflecting prism 71) as compared with the sixteenth embodiment, theformation is simple. Also, FIG. 29 shows an example wherein the adapteroptical system 50 having the same formation as that of the thirteenthembodiment is used. The opening part of the shutter 66 synchronouslyrotates so that the beam may not be intercepted. At this time, otherparts such as the image forming lens 63 and image taking device 53 mayalso rotate together with the shutter 66.

FIG. 30 shows unit formations of the eighteenth embodiment of thepresent invention. In FIG. 30A, the unit formation comprises the frontgroup unit 81 having the front groups 54a and 54b built-in, the reargroup--relay lens system--pupil image forming lens system unit 82 havingthe rear group 55, relay lens systems 52a, 52b and 52c and pupil imageforming lens system 61 built-in, the image forming lens system unit 83having the image forming lens systems 63a and 63b built-in and the imagetaking device unit 84 having the image taking devices 53a and 53bbuilt-in. By the way, the connecting part of the rear group--relay lenssystem--pupil image forming system unit 82 and the image forming lenssystem unit 83 corresponds to the border of the input section 25 andoutput section 24 shown in FIG. 5.

FIG. 30B shows a formation of the image forming lens system--imagetaking device unit 85 wherein, in FIG. 30A, the image forming lenssystems 63a and 63b and image taking devices 53a and 53b are made as oneunit.

FIG. 30C shows a formation in FIG. 30A of the objective optical systemunit 86 combining the front groups 54a and 54b in the front group unit81 and the rear group 55 in the rear group--relay lens system--pupilimage forming lens system unit 82, the relay lens system--pupil imageforming lens system unit 87 having the relay lens systems 52a, 52b and52c and pupil image forming lens system 61 built-in and the imageforming lens system--image taking device unit 85, the same as in FIG.30B.

In FIG. 30D, the objective optical system (that is, the front groups 54aand 54b and the rear group 55), relay lens systems 52a, 52b and 52c andpupil image forming lens system 61 are formed of the objective opticalsystem--relay lens system--pupil image forming system unit 88 and theimage forming lens system--image taking device unit 85 are made as oneunit.

In FIG. 30E, the objective optical system and relay lens systems 52a,52b and 52c are formed of the objective optical system--relay lenssystem unit 89 made one unit and the pupil image forming lens system 61,image forming lens systems 63a and 63b and image taking devices 53a and53b are formed of the pupil image forming lens system--image forminglens system--image taking device unit 90 are made as one unit.

In FIG. 30F, the front group unit 81, rear group 55 and relay lenssystems 52a, 52b and 52c are formed of the rear group--relay lens systemunit 91 and pupil image forming lens system--image forming lenssystem--image taking device unit 90 are made as one unit.

In FIG. 30G, the relay lens systems 52a, 52b and 52c are formed of therelay lens system unit 92, objective optical system unit 86 and pupilimage forming lens system--image forming lens system--image takingdevice unit 90 are made as one unit. By the way, in FIGS. 30B to 30G,the lens system within each unit is shown with the reference numeralomitted.

Also, in FIGS. 30A to 30G, the ocular adapter 45' shown in FIG. 16D maybe made connectable.

In FIG. 31, the front group unit 81 is explained further. FIG. 31A showsa front group unit 81 using a common front group 54. In case it isfitted, a pupil dividing type stereoendoscope in the related art will beable to be formed.

FIG. 31B shows the front group unit 81 of a visual field angle of 70degrees. FIG. 31C shows the front group unit 81 of a visual field angleof 40 degrees. When they are replaced, any desired visual field anglewill be obtained.

FIGS. 31D and 31E show a front group perspective unit 81 of a visualfield direction of 70 degrees. FIG. 31E is a view as seen from the rearof FIG. 31D. When the reflecting prism 71 is replaced, the front groupperspective unit 81 of any visual field direction will be able to beformed.

FIG. 31F shows the front group unit 81 in which the parallax is reducedand the optical axes of the front groups 54a and 54b are brought closeto each other to make the distance d' smaller than the other opticalaxis distance d. In FIGS. 31A to 31F, if the beams from the front groups54a and 54b are made substantially afocal beams, when the unit isdisplaced, a focus lag and image lag will be able to be controlled.

FIG. 32 shows a formation of the objective optical system unit.

FIG. 32A shows an objective optical system unit 86 comprising the frontgroup 54 and rear group 55 arranged to share the same optical axis. Whenit is used, the pupil dividing type stereoendoscope in the related artwill be able to be formed. FIG. 32B shows an objective optical systemunit 86 having the front groups 54a and 54b of a visual field angle of70 degrees. FIG. 32C is of an objective optical system unit 86 havingthe front groups 54a and 54b of a visual field angle of 40 degrees. Whenthese are replaced, any desired visual field angle will be obtained.

FIG. 32D is of a perspective objective optical system unit 86 of avisual field direction of 70 degrees. FIG. 32E is a front view of FIG.32D. When the reflecting prism 71 is replaced, a perspective objectiveoptical system unit of any visual field direction will be able to beformed. By the way, in FIG. 32E, the light guide is omitted.

FIG. 32F shows an objective optical system unit in which the parallax isreduced and the optical axes of the two front groups 54a and 54b arebrought close to each other so that the optical axis distance d' may besmaller than d, for example, in FIG. 32B and others.

FIG. 33 shows a formation of a unit including the rear group 55, relaylens systems 52a and 52b and pupil image forming lens system 61.

FIG. 33A shows the rear group--relay lens system--pupil image forminglens system unit 82 including the rear group 55, relay lens systems 52aand 52b and pupil image forming lens system 61. FIG. 33B shows the relaylens system--pupil image forming lens system unit 87 including the relaylens systems 52a and 52b and pupil image forming lens system 61. FIG.33C shows the rear group--relay lens system unit 91 including the reargroup 55 and relay lens systems 52a and 52b. FIG. 33 shows the relaylens system unit 92 comprising the relay lens systems 52a and 52b.

Any number of relaying times of the relay lens system can be used. Asrequired, different lengths for the inserted section different can beselected.

The respective units in the eighteenth embodiment can be formed byadopting a part of the optical system of the tenth to seventeenthembodiment.

According to the eighteenth embodiment, the stereoendoscope of theformation adapted to the using object can be selected and used. Theother effects are the same as the tenth to seventeenth embodiments.

The following nineteenth and twentieth embodiments are embodimentswherein formations (a) in the means and operations for solving the abovementioned problems are used. When a plurality of images taken in by anobjective optical system and having a parallax between them aretransmitted by a common image transmitting optical system, are taken andare selectively displayed by a displaying means, optimum stereo-imageswill be provided.

FIG. 34A shows a formation of a stereoendoscope apparatus 101 providedwith the nineteenth embodiment of the present invention and an operationmade by using the stereoendoscope 102 of the nineteenth embodiment. FIG.34B shows an arrangement of an objective optical system 121 as seen fromthe distal end surface of the stereoendoscope 102.

This stereoendoscope apparatus 101 comprises a stereoendoscope 102having an image taking means for taking a plurality of images having abuilt-in parallax, a CCU 103 processing signals for this imaging means,a distributor 104 connected to this CCU 103 and distributing videosignals, a color monitor 105 as plural displaying means displaying thevideo signals distributed by this distributor 104 and head mounteddisplays (abbreviated as HMD's) 106 and 107.

In FIG. 34A, a rigid inserted section 111 of the stereoendoscope 102 isinserted toward an affected part 114 from a hole 113 in an abdominalpart 112 of a patient. Two operators 115 and 116 respectively fit HMD'sto their head parts, observe the affected part 114 withstereo-inspection and treat the affected part 114 by using treatingtools 117 and 118. The treating tools 117 and 118 may be insertedthrough other holes or through channels in the stereoendoscope 102.

Also, another observer 119 (an assistant, nurse or spectator) observesthe same affected part with stereo-inspection by observing the colormonitor 105 with shutter spectacles 120 fitted.

The stereoendoscope 102 comprises an objective optical system 121, relayoptical system 122, adapter optical system 123 and image taking means124 in the order mentioned from the object side.

At least three images having a parallax between them and formed by theobjective optical system 121 are transmitted by one (or plural) relayoptical system 122 and are spatially (or timely) separated and formed byrespective image taking devices forming the image taking means 124. Theelectrical signals of the respective images photoelectrically convertedby the image taking means 124 are converted to video signals by the CCU103, are further divided into signals of any two images by thedistributor 104 and are displayed by the color monitor 105 and HMD's 106and 107 which are to be displaying means.

In this embodiment, when the various optical systems shown so far areused as combined with the objective optical system 121 and adapteroptical system 123, the stereo-image optimum to the respective operatorsand observers will be able to be effectively provided.

When a plurality of images are transmitted by one relay optical systembuilt-in in one tubular inserted section 111, only one hole 113 in theabdominal part 112 is required and the burden on the patient will beable to be reduced.

As shown, for example, in FIG. 34B, the objective optical system 121 isformed of six objective lens systems 121a to 121d arranged in thepositions separated by a fixed distance from the center axis at an angleof 60 degrees from the center axis of the inserted section. The siximages by these objective lens systems 121a to 121f are taken, forexample, by six image taking devices forming the image taking means 124through the common relay optical system 122 and the adapter opticalsystem 123 formed, for example, of three adapter lens systems.

According to this formation, by selecting the image, for example, by theobjective lens systems 121a and 121d, a stereo-image having a largeparallax can be obtained and, by selecting the image by the objectivelens systems 121b and 121e, a stereo-inspection having a large parallaxin the direction different by 60 degrees is possible. Further, byselecting the image by the objective lens systems 121c and 121f, astereo-inspection having a large parallax in the direction different by120 degrees is possible.

Further, by the combination in the above mentioned case, the parallaxwill become small. However, by selecting the image, for example, by theobjective lens systems 121a and 121c or the objective lens systems 121aand 121e, an image having a stereo-feel in various directions can beobtained.

By the way, a remote display selecting means whereby the operator 115using the displaying device can remotely select the two imagesdistributed by the distributor 104 to the displaying device side of theHMD 106 or the like by a wireless remote controlling apparatus usinginfrared rays or ultrasonic waves may be provided.

An observing direction displaying means is provided whereby, in case theimage by the objective lens systems (for example, 121b and 121e) in theparallax direction different from the parallax direction of a set ofobjective lens systems (for example, 121a and 121d) as a reference isselected, the parallax direction changing angle (in this case, 60degrees) will be displayed within the displaying device so that thedirection in which the operator 115 or the like is observing may besimply found.

By the way, in this embodiment, n (at least three or more) (in FIG. 34,n=6) objective images are transmitted by one relay optical system 122but may be transmitted by n-i relay optical systems (here, i=1 to n-1).

FIG. 35 shows a formation of the stereo-endoscope 131 of the twentiethembodiment of the present invention. FIG. 35A shows a general formationof the stereoendoscope 131. FIG. 35B shows an elevation as seen from thedistal end surface in FIG. 35A. FIG. 35C shows an arrangement of imagetaking devices as seen from the front surface side in FIG. 35A. In thisembodiment, too, several sets of stereo-images can be obtained.

Several front groups 133 (133a to 133f) forming an objective opticalsystem 132 arranged on the distal end side of the rigid inserted section111 take in images having a parallax between them and an image 135 isformed in substantially superimposed positions by one common rear group134, is relayed several times by one common relay optical system andbecomes a final image 137.

This final image 137 is of several superimposed images. These imageshave their pupils spatially separated by a pupil image forming lenssystem 138 and, further, respective images 141 (141a to 141f) are formedon CCD's 140 (140a to 140f) by image forming lenses 139.

In this embodiment, six images having a parallax between them can beobtained. When two of the images are selected and displayed, the imageshaving various stereo-feels and parallaxes will be able to bestereo-inspected. Also, several persons can stereo-observe in separatedirections.

FIGS. 36A to 36F show distal end side formations of the stereoendoscopeof the twenty-first embodiment of the present invention. FIG. 36B is anelevation of FIG. 36A. FIG. 36C shows an optical system as seen from theside of FIG. 36A. FIG. 36D is an elevation of FIG. 36C. FIG. 36E showsFIG. 36C as bent. FIG. 36F is an elevation of FIG. 36E.

In this embodiment, the inserted section 152 can be bent on the distalend side.

A front group optical system 153, a rear group 154a forming a relayoptical system 154 and a relay lens system 154b are arranged from thedistal end side within the inserted section 152. The distal end section155 of the inserted section covering the objective optical system 153 isformed of a tubular frame having a curvable hose structure. The proximalside from the relay optical system 154 is formed of a rigid tubularframe.

Mirrors 158 and 159 are arranged between concave lenses 156a and 156b asof a front group and convex lenses 157a and 157b forming the objectiveoptical system 153 and are rotatable respectively around axes 161 and162.

When the mirrors 158 and 159 are rotated simultaneously with curvingfrom the straight seen state in FIG. 36C, the distal end section 155will be curved to be bent as in FIGS. 36E and 36F. According to thisembodiment, the observation can be made with the distal end sectionbent. The other effects are the same as in the first embodiment andothers.

FIG. 37 shows a formation on the distal end side of the stereoendoscopeof the twenty-second embodiment of the present invention. Thisembodiment is a combination of the twentieth embodiment wherein severalsets of stereo-images can be obtained and the twenty-first embodimenthaving a bendable structure.

Usually, in an endoscope operation, the endoscope does not enterdirectly into the abdominal part but is inserted instead through atragacanth 171. The thinner the tragacanth 171, the less the distress ofthe patient. On the other hand, in case several operators jointlyoperate, the observation can conveniently be made in the separaterespective directions.

However, there is a limit to how much the parallax may be increased andthe parallax can not be made greater than the outside diameter of thedistal end section. This embodiment can cope with such circumstances andmakes it possible to observe in separate directions.

In this embodiment, two bendable distal end sections 155 and 155' areprovided forward of the relay optical system 154 and objective opticalsystems 153 and 153' of the same structure as in the twentiethembodiment in FIG. 36 are contained within the respective distal endsections 155 and 155'. The same members as shown in FIG. 36 within thedistal end section 155 shall bear the same reference numerals, the samemembers as shown in FIG. 36 within the other distal end section 155'shall bear the same reference numerals fitted with ' and theirexplanation shall be omitted.

According to this embodiment, when the distal end section is insertedwithin the tragacanth 171, it will be seen as straight as in FIG. 36C.When the distal end section comes out of the tragacanth 171, it will bebent as in FIG. 37A and several observers will be able to observe inseparate directions through one thin relay optical system 154.

By the way, for example, in the first embodiment, each of the objectiveoptical systems 21a and 21b may be formed of an anamorphic opticalsystem wherein the image forming magnification in the horizontaldirection can be made smaller than the image forming magnification inthe vertical direction (intersecting at right angles with thishorizontal direction).

In the case of this formation, particularly, in case a common imagetaking device 23 is adopted, the two right and left images will be ableto be prevented from being superimposed and the right and left imagetaking ranges in the image taking device 23 will be able to besubstantially expanded.

In the function of transmitting images by the relay optical system 22,because the right and left images can be intercepted less than in thecase of no anamorphic optical system, that much, the objective opticalsystems 21a and 21b will be able to be arranged as having increasedseparation from each other (with the optical axis distance d larger) anda picture image having a higher stereo-feel will be able to be obtained.

In this case, in the CCU 4, the signal of extending the picture image inthe horizontal direction or compressing the picture image in thevertical direction may be processed.

By the way, the relay optical system 22 may be also formed of ananamorphic optical system. Even in the other embodiments, the objectiveoptical system, relay optical system and adapter optical system may beformed of anamorphic optical systems.

By the way, in the lens data of the respective embodiments, in case thesame lenses are paired in the objective optical system, adapter opticalsystem and the like, only the lens data of one of the pair will beshown. In the respective embodiments, the relay lens optical systemformed of a homogeneous bar-like lens is shown. However, even in case arefractive index distributing type lens is formed of suchnon-homogeneous rod as of a Shelphock (trade name) and is used for therelay optical system (image transmitting optical system), the presentinvention will be effective.

By the way, the embodiment wherein a plurality of images having aparallax are formed in spatially separated positions by the objectiveoptical system and the embodiment wherein a plurality of images having aparallax are formed in spatially substantially coinciding positions havebeen explained above. However, the case of their intermediate functions,that is, the case where a plurality of images having a parallax areformed in spatially at least partly superimposed positions and the casethat a plurality of images having a parallax are formed in spatially atleast partly separated positions belong to the present invention. Also,the case of applying an image by an objective optical system to the casethat the image by the objective optical system is transmitted by suchimage transmitting optical system as the relay optical system belongs tothe present invention.

As explained above, as the stereoendoscope in the fist to twenty-secondembodiments is provided with an objective optical system having aplurality of incident pupils formed in different positions and forming aplurality of images having a parallax between them having passed throughthese plural incident pupils and a common image transmitting opticalsystem transmitting the plural images having a parallax between them,the parallax will be able to be made large by the optical system, asufficient stereo-feel will be obtained, the parts of the light pathtransmitting a plurality of images will be able to be made common bymaking the image transmitting optical system common, the number of theparts will be able to be reduced and the dispersion of plural images byproduction errors will be able to be extremely prevented.

When a stereoendoscope is formed by providing a plurality of objectiveoptical systems arranged in parallel, separating plural images having aparallax and forming images and a common image transmitting opticalsystem transmitting the plurality of images, the parallax will be ableto be made large by the optical system, a sufficient stereo-feel will beobtained, the parts of the light path transmitting the plurality ofimages will be able to be made common by making the image transmittingoptical system common, the number of the parts will be able to bereduced and the dispersion of plural images by production errors will beable to be extremely prevented. Further, as the images transmitted bythe image transmitting optical system are spatially separated, thestereo-inspection will be made possible by the image taking means andocular optical system without using an image separating means.

Also, when a stereoendoscope is formed by providing several front groupoptical systems, common rear group optical systems forming objectiveoptical systems forming a plurality of images having a parallax inspatially substantially coinciding positions and a common imagetransmitting optical system transmitting the plurality of images, theparallax will be able to be made large by the optical system, asufficient stereo-feel will be obtained, the parts of the light pathtransmitting the plurality of images will be able to be made common bymaking the image transmitting optical system common, the number of theparts will be able to be reduced and the dispersion of the plurality ofimages by production errors will be able to be extremely prevented. Whena common rear group optical system is used in the objective opticalsystem part, many parts will be able to be used in common and aplurality of picture images less influenced by production errors andhigh in quality will be obtained.

Further, there is a stereo-inspectable endoscope in U.S. Pat. No.5,191,203 shown in FIG. 38A wherein an objective optical system 500 isformed of collimator lenses 501 and a pair of left and right imageforming lenses 502a and 502b arranged in the order mentioned from theobject side.

In the objective optical system of the stereoendoscope of this relatedart, there are the following three problems:

(1) When the picture angle is to be made large, the inward angle willnot be able to be made large and the stereo-feel will reduce.

As in FIG. 38B, in case the picture angle is to be made large, it willbe necessary that the power arrangement of the collimator lenses 501will be negative and positive in the order from the object side. Whenthe power of the negative lens 503 on the object side is made large, thepicture angle will be able to be made large. However, in this case, thefocal distance fc of the collimator lenses 501 will become larger thanthe object distance s and the inward angle a will become small by thefollowing formula:

    α=2·arctan (d/2 fc)

wherein d represents an optical axis distance between the two imageforming lenses 502a and 502b.

(2) A relative error between the left and right images is likely tooccur.

The relative error between the right and left images is produced mostlyin the parts of the left and right separate bodies by a surface shapeerror, surface distance error, eccentricity error or the like betweenright and left independent lens systems. In the prior example, the partsof the left and right separate bodies (the parts having left and rightseparate optical axes) correspond to the image forming lenses 502a and502b which are so many that an error is likely to occur. When a relativelag (focusing, eccentricity or the like) is produced between the leftand right images, the left and right images will become difficult toresolve, resulting in fatigue.

(3) It is difficult to adjust the eccentricity error of the left andright images.

In order to adjust the eccentricity error of the left and right images,the lens or CCD of the left and right separate body parts must beadjusted. However, in the prior example, either the lens or the CCD isin a position through the other part (in this case, the collimator lens501) from the distal end section of the endoscope and is difficult toadjust.

The twenty-third to twenty-fifth embodiments provide a stereoendoscopewherein the picture angle and stereo-feel (inward angle) can be set tobe optimum, the error between the left and right images is small and iseasily adjustable, resulting in less fatigue, which shall be explainedbelow.

In the stereoendoscope of these embodiments, there are an elongateinserted section, an objective optical system arranged within the distalend of the inserted section and an image taking means arranged withinthe inserted section for taking object images formed by the objectiveoptical system. The objective optical system is formed of two negativelenses and one coaxial positive lens arranged in parallel with eachother in the order mentioned from the object side. The inward angle isdetermined by the optical axis distance between the two negative lenses,therefore the picture angle and stereo-feel (inward angle) can be set tobe optimum, the error between the left and right images is small and iseasy to adjust and the fatigue feel can be reduced. in thestereoendoscope having an elongate inserted section,

In the twenty-third embodiment, the objective optical system is appliedto a so-called electronic scope having a CCD in the distal end part ofthe inserted section of the endoscope.

As shown in FIG. 39, a stereoendoscope apparatus 201 comprises astereoendoscope 202 of the twenty-third embodiment having an imagetaking optical system for stereo-inspection built-in, a light sourceapparatus 203 feeding an illuminating light to an illuminating lighttransmitting means transmitting the illuminating light and provided inthis stereoendoscope 202, a camera controlling unit (abbreviated as CCUhereinafter) processing signals for an image taking means built-in inthis stereoendoscope 202, a scan converter 205 converting to a videosignal the signal put out of this CCU 204, a color monitor 206displaying the video signal put out of this scan converter 205 andshutter spectacles 207 having a shutter function of stereo-perceivingthe picture image displayed by this color monitor 206.

The stereoendoscope 202 has an elongate inserted section 208 to beinserted into a body cavity or the like and a gripped section 209 to begripped by the operator and formed to be thick at the proximal end ofthis inserted section. This inserted section 208 is formed of acylindrical metallic hose high in the flexibility and a soft jacket tubemade of a metallic mesh and resin or the like. The distal end section216 of the inserted section 208 is formed of a cylindrical rigid jackettube made of such metal as stainless steel. An objective optical system218 and two image taking devices 220a and 220b (for example, CCD's) areenclosed in the distal end section 216. By the way, the entire insertedsection may be formed of a rigid jacket tube, just as in the distal endsection.

This stereoendoscope has a light guide 215 as an illuminating lighttransmitting means transmitting the illuminating light fed from thelight source apparatus 203 and an illuminating optical system (notillustrated) for emitting the transmitted illuminating light through anilluminating window just as in the ordinary endoscope. Two observedimages having a parallax are obtained so that the object illuminated bythis illuminating optical system may be stereo-inspected and has anobserving optical system comprising the optical system 218 and two imagetaking devices 220a and 220b.

By the way, this embodiment includes an example wherein two imageshaving a parallax are formed by the image taking devices 220a and 220bhaving a photoelectrically converting function as an observing opticalsystem and is therefore also called an image taking optical system.

The gripped section 209 is provided with a light guide mouthpiece 210 towhich a light guide cable 211 is removably connected at one end. A lightguide connector 212 at the other end of the light guide cable 211 isremovably connected to the light source apparatus 203.

A lamp 213 generating a white illuminating light and a lens 214condensing this white light are arranged within the light sourceapparatus 203. The illuminating light condensed by this lens 214 isradiated on the end surface of the light guide connector 212, istransmitted by the light guide within the light guide cable 211, istransmitted from the light guide mouthpiece 210 to the light guide 215side within the stereoendoscope 202 and is fed.

The light guide 215 as an illuminating light transmitting means is bentwithin the gripped section 209 and is inserted through the insertedsection 208. This light guide 215 transmits the fed illuminating lightand emits the illuminating light forward from the distal end surfacefixed to the distal end section 216 of the inserted section 216.

An object (indicated by the arrow in FIG. 39) 217 illuminated by thisilluminating light has optical images (219a and 219b in FIG. 39) havinga parallax between them formed in image forming positions by theobjective optical system 218 fitted to an observing window arrangedadjacently to the illuminating window within the distal end section.These images 219a and 219b are formed on the photoelectric convertingsurfaces (image taking surfaces) of the image taking devices 220a and220b arranged the same within the distal end of the inserted section.

As shown in FIG. 40, the objective optical system 218 is formed of leftand right separate negative lenses 221a and 221b and an axiallysymmetrical positive lens group 222 arranged in parallel with each otherin the order mentioned from the object side. The light passing through adiaphragm opening 223b of the light from the object forms an image onthe image taking device 220a and the light having passed through adiaphragm opening 223a forms an image on the image taking device 220b.By the way, a cover glass 240 made of parallel plane plates is arrangedon the object side of the negative lenses 221a and 221b.

Here, the lens data of the objective optical system 218 of thisembodiment are shown in Table 10.

In FIG. 39, the image taking devices 220a and 220b have, for example,square image taking surfaces. The vertical or horizontal direction ofthis image taking surface coincides with the horizontal direction inwhich the two diaphragm openings 223a and 223b are separated andarranged.

The image taking devices 220a and 220b are extended out and areconnected with the CCU 204 by the signal cable 224. The image takingsignal photoelectrically converted by the image taking devices 220a and220b is processed in the CCU 204. The image signal processed in this CCU4 is further put into a scan converter 205 and is converted to a videosignal. The video signal is put out in a color monitor 206 in which thepicture images having a parallax between each other and separatelyformed through the two diaphragm openings 223a and 223b are alternatelydisplayed and the operator can observe and stereo-inspect the pictureimages with the shutter spectacles.

FIG. 41 shows a power arrangement of the objective optical system 218 inthis embodiment. The inward angle a determining the magnitude of thestereo-feel is as follows from the optical axis distance d between thetwo negative lenses 221a and 221b and the object distance s:

    tan (α/2)=d/(2s).

That is to say, as shown in FIG. 41, the inward angle of the objectiveoptical system in this embodiment is determined by the optical axisdistance d between the two negative lenses and does not depend on thepicture angle. Further, as the left and right separate parts are onlythe negative lenses 221a and 221b, no relative error will be likely tobe produced. Therefore, there can be obtained the following results:

(1) As the inward angle is determined by the optical axis distancebetween the two negative lenses and the inward angle and picture anglecan be independently set, the picture angle will be able to made largewith the inward angle kept large.

(2) As the main cause of the relative error between the left and rightimages is only the negative lens, the relative error between the leftand right images will be little.

(3) As the left and right separate parts for adjusting the error betweenthe left and right images are on the distal end side of the endoscope,they will be easy to adjust.

FIG. 42 shows a frame structure of the distal end section 216 of thestereoendoscope 202 in this embodiment. The frame structure comprises aninner tube 225 holding lenses and a CCD and an outer tube 226 enclosingthe inner tube 225, an illuminating light guide and forceps channel notillustrated.

In the objective optical system of the prior example in FIG. 38A, as theleft and right separate bodies for adjusting the eccentricity of theleft and right images are in the positions through the collimator lensfrom the distal end within the inner tube, when they are to be adjusted,adjusting grooves, screws and adjusting spaces will have to be preparedin the inner tube and the inner tube will not be able to be made theinner tube 25 of such simple structure as in FIG. 42 and will be largein the outside diameter. on the other hand, in this embodiment, as thetwo negative lenses 221a and 221b which are the left and right separateparts to be adjusted are outside the distal end of the inner tube 225,the positions of the negative lenses 221a and 221b will be able to besimply adjusted without requiring a special structure for the inner tube225. The negative lenses 221a and 221b are adjusted in the position andare then bonded and fixed and the inner tube 225 is inserted into theouter tube 226 to complete the stereoendoscope.

The twenty-fourth embodiment shall be explained in the following withreference to FIG. 43. As the twenty-fourth embodiment is substantiallythe same as the twenty-third embodiment, only the different formationsshall be explained.

In the twenty-fourth embodiment, the objective optical system of thestereoendoscope according to the present invention is applied to aso-called rigid endoscope wherein an image is transmitted to theproximal side by an objective optical system 218 and a transmittingoptical system 227 arranged in an inserted section consisting of acylindrical rigid jacket tube and is taken.

As shown in FIG. 43, images 219a and 219b formed by the objectiveoptical system 218 are relayed by relay lenses 227a, 227b and 227c whichare of a transmitting optical system 227 and are then formed on CCD's229a and 229b by an image taking lens 228. All the lenses other than thenegative lenses 221a and 221b at the distal end are coaxial. The images,that is, pupils of the diaphragm openings 223a and 223b are transmittedrespectively to positions 250, 251, 252 and 253. The other formations,operations and effects are the same as in the twenty-third embodiment.

Here, the lens data of the objective optical system 218 and transmittingoptical system 227 in this embodiment are shown in Table 11.

The image taking lens 228 in this embodiment is one coaxial lens systembut the two pupils are separated in the position 253. Therefore, as theimage forming lens of the image taking lens shown in the following,image forming lenses arranged in parallel with each other may be usedafter the pupil 253 to form images.

The twenty-fifth embodiment shall be explained in the following withreference to FIGS. 44 and 45. As this embodiment is substantially thesame as the twenty-fourth embodiment, only the different formationsshall be explained.

The twenty-fifth embodiment is an embodiment as applied to a rigidendoscope just as in the twenty-fourth embodiment.

In this embodiment, as shown in FIG. 44, the basic formation of theobjective optical system 218 is the same as in the twenty-fourthembodiment. However, the image 219a formed of the light passing throughthe diaphragm opening 223b of the light from the object and the image219b formed of the light passing through the diaphragm opening 223a arepartially superimposed.

The images 219a and 219b formed by the objective optical system 218 arerelayed by the relay lenses 227a and 227b as shown in FIG. 45. Theimages are then formed to be infinite by the pupil image forming lens230 and are formed respectively on the CCD's 229a and 229b by a pair ofleft and right image forming lenses 231a and 231b. The images (pupils)of the diaphragm openings 223a and 223b are transmitted respectively tothe positions 254, 255 and 256. As the two pupils have been separated inthe position 256, the two partially superimposed images 233a and 233brelayed by the relay lenses 227a and 227b are formed separately by theimage forming lenses 231a and 231b. The other formations, operations andeffects are the same as in the twenty-fourth embodiment.

Here, the lens data of the objective optical system 218 and transmittingoptical system 227 of this embodiment are shown in Table 12.

In the 25th embodiment, the left and right separate parts are presentnot only in the distal end section (the negative lenses 221a and 221b)but also within the image taking lens 232 (the image forming lenses 231aand 231b). Therefore, when the negative lenses are not adjusted but theimage forming lenses are adjusted, the eccentricity error between theleft and right images will be able to be adjusted.

However, in case the stereoendoscope 202 is made removable between theinput section (until the transmitting optical system 227 or until thepupil image forming lens) and the output section (after the pupil imageforming lens 230 or after the image forming lenses 231a and 231b), itwill be necessary for the input section and output section to beindependently adjusted. Therefore, even during such adjustment of theinput section, the objective optical system of the present invention isvery effective.

A plural visual field direction type endoscope after the 26th embodimentshall be explained in the following.

The endoscope apparatus 310 shown in FIG. 46 has an inserted section302, an endoscope 311 in which the visual field direction is changeablein the 26th embodiment, a camera 304, monitor 305 and light sourceapparatus 307.

An objective optical system having a plurality of visual fielddirections and a light guide illuminating the respective visual fielddirections are incorporated in the distal end section 301 of theinserted section 302 of the endoscope 311. The inserted section 302 isprovided with a relay lens system which is an image and pupiltransmitting optical system following the objective optical system. Anocular optical system is arranged in the proximal section 303 of theendoscope 311. The camera 304 can be fitted in the rear of the ocularoptical system. Here, the proximal section 303 of the endoscope 311 andthe camera 304 are formed to be integral or removable. The object havinghad the image taken by the camera 304 is displayed to be observable bythe observer as an endoscope picture image finally in the monitor 305.

The illuminating light from the light source apparatus 307 passesthrough the light guide cable 306 and illuminates the respective visualfield directions through the proximal section 303, inserted section 302and distal end section 301.

The details of the optical system of the endoscope 311 shall beexplained as follows:

On the optical systems of the endoscope of the 26th embodiment, a pupildivision is utilized in the objective optical system and an ocularoptical system is formed.

The pupil dividing system is fundamentally formed of an optical systemhaving one optical axis but, in order to make a plural visual fielddirection type, a lens group corresponding to a plurality of visualfield directions is arranged in front of the optical system. The pluralvisual field direction type optical system having adopted this pupildividing system is formed of a front side lens group formed the same ina plurality of visual field directions and arranged in the respectiveplurality of visual field directions, a prism for forming images in theplurality of visual field directions in the rear step of the front sidelens group corresponding to the plurality of visual field directions, abrightness diaphragm having a plurality of openings arranged nearpupils, thereby forming a plurality of pupils and a rear side lens groupforming one image of superimposed beams in the plurality of visual fielddirections in the order mentioned from the object side.

The inherent one beam of the optical system is divided near the pupil bythe brightness diaphragm 321 having two openings and is shown in FIG.37B. The beam passing through one opening of the brightness diaphragm321 is seen straight-on as it is and the beam passing through the otheropening of the brightness diaphragm 321 is perspectively seen in thevisual field direction by the prism. Here, the two images in the visualfield direction are formed to be superimposed on the image surface.

The formation of the optical system relating to this embodiment shall beexplained concretely with reference to FIG. 47A. The optical systemshown in FIG. 47A comprises an objective optical system 322, a set ofrelay lens system 323 as a transmitting optical system and an ocularoptical system 324.

The objective optical system 322 has a front side lens group 329acomprising two objective lenses 325 and 326 arranged in the positionsnearest to the object and directed respectively in the straight seendirection and side seen direction, a first prism 327 making the beamfrom the two objective lenses 325 and 326 incident on differentsurfaces, a second prism 328 making the beam from the first prism 327incident on the same surface and a brightness diaphragm 321 for dividingthe pupil into a plurality of pupils in response to the visual fielddirection and has a rear side lens group 329b for converging the beamfrom the pupils and forming the object image arranged in the rear ofthis front side lens group 329a. In the drawing, the one-point chainlines represent the optical axes of the respective visual fielddirections.

The image in the direction as seen straight-on in this optical system isformed as follows. The rays having passed through the objective lens 326pass through the surface 331 of the first prism 327 to the joint surface332. The joint surface 332 on the first prism side 327 is black-paintedso as to pass no others than the rays effective to prevent detrimentalflares and is made a flare diaphragm. Because the first and secondprisms 327 and 328 are made of the same glass material, their refractiveindices are equal and the rays pass through the surface 332 withoutbeing refracted. Then an image I1 having the lower side of thebrightness diaphragm 321 as a pupil surface and having the optical axisof this rear side lens group 329b as a center axis by the rear side lensgroup 329b is formed.

On the other hand, the image in the perspectively seen direction isformed as follows. The rays passing through the perspectively seeingobjective lens 325 pass through the surface 333 of the first prism 327to the joint surface 332. At this time, the rays forming the image inthe perspectively seen direction proceed straight through the jointsurface without being refracted the same as the straight-on seen rays.

The joint surface 332 on the first prism side 327 is made a flarediaphragm passing no others than the rays effective to preventdetrimental flares. As the optical axis in the straight-on seendirection and the optical axis in the perspectively seen directionintersect with each other on the joint surface, the same flare diaphragmwill effectively function on the rays in both directions. The straightproceeding rays in the perspectively seen direction are reflected by themirror-processed surface 334 and go again to the surface 332 on thesecond prism 328 side.

The surface 332 on the second prism 328 side is mirror-processed in therange of not intercepting the straight-on seen rays and perspectivelyseen rays separated by the pupil division and in the range of coveringthe reflected perspectively seen rays reflected by the surface 334.Therefore, the rays in the perspectively seen direction reflected by thesurface 334 without being perceived pass on the upper side of thebrightness diaphragm 321 and are made the image II having the opticalaxis of the rear side lens group 329b as a center axis by this rear sidelens group 329, just as the straight-on seen rays and the image isformed.

The images I1 in the plurality of visual field directions made by theobjective optical system 322 and the pupil P1 are transmitted in theocular optical system direction by the relay lens system 323. In thedrawing, the reference numeral P2 represents a plurality of pupilscorresponding to the respective visual field directions transmitted bythe relay lens. An image I2 is formed between the relay lens system 323and ocular optical system 324. A plurality of pupils P3 corresponding tothe respective visual field directions are obtained through the ocularoptical system 324.

When the observer moves the position of his pupil to the position of thepupil transmitted in the visual field direction he wants to observe, hewill be able to select the visual field direction.

In this embodiment, the objective optical system is originally designedas a coaxial optical system but not as an eccentric optical system andis formed to be bent with a prism for a pupil in a different visualfield direction. That is to say, the optical axis of the objective lens326 is on the extended line of the optical axis of the rear side lensgroup 329b through the joint surface 332 and the optical axis of theobjective lens 325 is on the extended line of the optical axis of therear side lens group 329b reflected on the joint surface 332 and furtherreflected on the reflecting surface 334. Therefore, between the opticalsystem comprising two negative lenses and a prism and the optical systemin the rear of it, even if the beam is not afocal, two imagessuperimposed before the relay system will be able to be formed.

In this embodiment, as the pupil division is utilized and originally oneoptical system is used, with a formation of few lenses, a high picturequality will be obtained, if the means for determining plural pupils isin a position conjugate with the pupil position of the objective opticalsystem, it may be the position of the pupil P2 of the relay system 323or any other part and, as the objective system and transmitting opticalsystem have no visual field direction switching apparatus, the structurewill be simple and the ease of assembly will be high.

An example of designing an actual objective optical system is shown inFIG. 48 and its numerical value data are mentioned in Table 13. By theway, in the formation shown in FIG. 48, the part shown as the rear sidelens group 329b in FIG. 47A is formed of a lens 329" jointed to a prismand three jointed lenses 329'.

In this embodiment, because the formed image is one, the followingeffects will be able to be obtained.

That is to say, as the objective optical system of the plural visualfield direction type endoscope has a plurality of visual fielddirections, a plurality of pupils corresponding at 1 to 1 to the visualfield directions and one image, the one image is a superimposition ofimages in a plurality of visual field directions, the optical axis ofthe plurality of visual field directions coincides with the optical axisof the transmitting system in the position of the image and, on the wayof the transmission in the transmitting optical system after the image,one image and a plurality of pupils will be transmitted without beingintercepted.

Therefore, in this embodiment, after the transmitting optical system,the visual field direction can be selected and no movable part isrequired in the objective optical system and transmitting optical systemfor selecting the visual field direction. Further, in this embodiment,because the objective optical system and the like have no visual fielddirection switching apparatus, the structure will be simple and the easeof assembly will be high. Also, because no polarization is used, therewill be no deterioration of the image in the peripheral part by therotation in the polarizing direction.

These effects will be the same even in case the pupil dividing means isin the transmitting optical system or image forming optical system.

The 27th embodiment shall be explained in the following with referenceto FIGS. 49 to 54.

In the endoscope of this embodiment, an eccentric optical system isutilized for the objective optical system, an image forming opticalsystem and solid state image taking device are used instead of theocular optical system in the 26th embodiment and no optical visual fielddirection selecting means is provided.

FIG. 49A shows a formation of an optical system arranged within theendoscope of this embodiment.

The optical system of this embodiment comprises in the order mentionedfrom the distal end side an objective optical system 341, relay lenssystem 342, pupil image forming lens 343, such reflecting members 344aand 344b as a pupil separating optical member 344c and mirror and twosolid state image taking devices 346a and 346b as an image taking means.By the way, though only one relay lens system is shown, it is naturalthat a plurality of relay lens systems may be used as required. Theimage forming lenses 345a and 345b form the image forming opticalsystem.

In the objective optical system 341, a front optical system 347comprising substantially afocal lens groups 347a and 347b independent ofeach other and having two straight-on seen and perspectively seen visualfield directions and pupils P11 corresponding to these visual fielddirections is arranged in the front group and a rear side lens system348 having a size capable of transmitting the beams from the pluralityof pupils P11 to the image without being intercepted and forming onesuperimposed image of the beams in the plurality of visual fielddirections is arranged in the rear group.

The relay lens system 342 forms the images of the pupils P11 as pupilsP12, forms the image I11 as an image I12 and transmits them to a pupilimage forming lens 343. The pupil image forming lens 343 transmits thepupils transmitted from the relay lens system 342 to the side of a pupilseparating optical member 344c having a plurality of reflectingsurfaces. This pupil separating optical member 344c receives a pluralityof pupils P13 and separates and delivers them in respectively differentdirections, that is, to the reflecting members 344a and 344b.

The reflecting members 344a and 344b reflect the beams passing throughthe separated respective pupils, that is, in the illustration, the twopupils corresponding to the optical system in the straight-on seendirection and the optical system in the perspectively seen directionrespectively toward the lens systems 345a and 345b. The lens systems345a and 345b form images corresponding to the respective pupils in thesolid state image taking devices 346a and 346b.

In this formation, first the rays in the respective visual fielddirections pass through two substantially afocal lens groups 347a and347b forming the front optical system 347, then the optical axes in therespective visual field directions are bent by the rear side lens system348 and the image Ill is formed on the optical axis of the rear sidelens system 348.

In this embodiment, substantially the same basic formation whichrealizes the perspective view made by the prisms 327 and 328 in the 26thembodiment is used. Here, the perspective view prism may be a 300 prismshown in the publications of Japanese Patent Applications Laid OpenNos.140313/1985, 91333/1975 and 108013/1990 or a 700 prism or 1100 prismshown in the publication of Japanese Patent Application Laid OpenNo.87403/1984.

Also, the objective optical system 341 may be the front optical system347c including the same prisms as the prisms 327 and 328 of the abovementioned embodiment as in FIG. 50, that is, may be a straight-on seeingand perspectively seeing optical system in common. Or the objectiveoptical system 341 may realize a perspective view by utilizingrefraction with a wedge prism 349 placed near the pupil P11 as in FIG.51. In this formation, the lens group to be used respectively in thestraight seen direction and the perspectively seen direction may besubstantially the same lens group differing only in length, and theperspectively seeing lens group may be inclined to the straight-onseeing lens group and the wedge prism 349 may be arranged in the rear ofit.

Otherwise, as shown in FIG. 54, the objective optical system 341 mayhave three or more visual field directions if in a range that the imageand pupil are not intercepted by the relay lens system arranged in therear. In the illustrated example are shown the most distal end sidelenses 350, 351 and 352 forming respective lens groups respectively of 0degrees (straight-on seen), 30 degrees (perspectively seen) and 70degrees (perspectively seen).

As shown in FIG. 49A, the beam from the objective optical system 341forms an image I12 in the rear of the relay lens system just as in the26th embodiment by the relay lens system 342. Of the rays in therespective visual field directions forming the image I12 made in therear of the relay lens system 342, the beams of the two pupils differingin the visual field direction are respectively separated by the pupilseparating optical member 344c arranged in the rear of the pupil imageforming lens 343.

This pupil separating optical member 344c is, for example, a prismarranged near the pupil P13 transmitted by the relay lens system 342 andformed as an image by the pupil image forming lens 343. The separatedbeams in the respective visual field directions are reflectedrespectively by the reflecting members 344a and 344b and are formed asimages respectively on the image taking devices 346a and 346b throughthe lens systems 345a and 345b.

In this embodiment, by the pupil image forming lens 343 forming imagesof pupils, the optical axes in the respective visual field directionsare made substantially parallel with the optical axis of the relay lenssystem 342 and the object point is formed as an image to infinity. Bythe way, the image may be formed so as not to be superimposed on onesolid state image taking device.

According to this embodiment, images differing in the visual fielddirection can be independently taken by a plurality of solid state imagetaking devices and the number of visual fields and the visual fielddirection can be easily selected by the objective optical system.Without an optical visual field direction switching means, images in allthe visual field directions are taken in. As in the illustrated example,in the formation using a plurality of solid state image taking devices,the outputs of the respective image taking devices are selected byswitching the switch and the signals are processed as determined and canbe displayed.

In the formation utilizing one solid state image taking device, therespective images different in the visual field direction may beselected by a signal processing means connected to the later step. Thepicture image in only one visual field direction can be displayed in amonitor.

That is to say, in this embodiment, without moving the optical system orwithout optically switching the visual field direction, the visual fielddirection can be changed. Also, depending on the way of processing thesignal, a plurality of images in the visual field direction can besimultaneously displayed in one or a plurality of monitors.

An example of designing an objective optical system is shown in FIG. 52.Also, an example of designing an objective optical system and relay lenssystem as combined is shown in FIG. 53. In the drawings, the referencenumeral 354 represents an objective optical system and the referencenumeral 355 represents a relay lens system. The lens data are mentionedin Table 14.

By the way, just as in the 26th embodiment, the diaphragm determiningthe pupil may be in the objective optical system, may be in the pupilposition in the conjugate relay lens system or may be in the pupilposition near the pupil dividing optical member.

In FIG. 49B is shown a modification of the 27th embodiment. In thismodification, a pupil image P13 is formed of dispersed beams orconverged beams by the pupil image forming lens 356 provided instead ofthe pupil image forming lens 343. A focal beams are then formed by thelens 357 making the beams parallel and the beams are further formed asimages by the image taking devices 346a and 346b through the imageforming lenses 345a and 345b. In this modification, a reflexing prism asa pupil dividing optical member is unnecessary. The diaphragm may bearranged above the pupil position P13 in the drawing, in the relay lenssystem or in the pupil position in the objective optical system. Theother same formations and operations as in the 27th embodiment shallbear the same reference numerals and shall not be explained here.

The 28th embodiment of the present invention shall be explained in thefollowing with reference to FIGS. 55 to 58B.

In the formation of the 28th embodiment, an image forming optical systemand a solid state image taking device are provided the same as in the27th embodiment and further an optical visual field direction switchingmeans is arranged.

The objective optical system in this embodiment may be the pupildividing system in the 26th embodiment or may be formed of thesubstantially afocal plurality of optical systems and rear opticalsystems in the 27th embodiment. This embodiment is different from theabove mentioned respective embodiments in the formation of the opticalsystem and the like arranged in the rear of the relay lens systemarranged in the rear of the objective optical system.

As shown in FIG. 55, the optical system in this embodiment comprises alens system 361 for making the light which was once formed as an imageby a relay lens system in the rear of the relay lens system (notillustrated) and then became dispersed beams in the respective visualfield directions parallel with the optical axis of the relay lens, apupil switching apparatus 362 as a selecting means switching the beamsin the respective visual field directions made parallel in response tothe respective pupils and arranged near the pupils to be formed asimages through the lens system 361 and an image forming lens system 363forming images of the rays selected by the pupil switching device 362 onthe solid-state image taking device 364.

The rays in the respective visual field directions forming the image I21formed in the rear of the relay lens system are made parallel with theoptical axis of the relay lens system by the lens system 361. By theswitching apparatus 362 near the pupil position, the rays passingthrough the other images than in the visual field direction the observerwants to observe are intercepted. The intercepting means as a selectingmeans may be a mechanically moved shielding plate or may be a liquidcrystal shutter switch to be on/off.

The selecting means may be such image rotator 365 as in FIGS. 56A and56B to be moved to switch the visual field direction. The referencenumeral 366 represents an image forming lens system forming an image ofthe rays obtained by the image rotator 365 on the solid state imagetaking device. By the way, FIGS. 56A and 56B show that the visual fielddirection is switched by moving the image rotator 365.

Also, as shown in FIG. 57, the selecting means may be moved to theposition of the visual field direction desired to be observed integrallywith the image forming lens system 365 and solid state image takingdevice 364 to switch the visual field direction. Only the image in theselected visual field direction is formed on the solid state imageforming device 364.

The effect of this embodiment is that the visual field direction can bechanged in a small space.

By the way, in case the pupil and image made by the objective opticalsystem are transmitted by the relay lens system and the pupil dividingmeans is arranged after the relay lens system, the brightness diaphragm321 can be omitted.

The formations of the 27th and 28th embodiments have an image takingmeans and may be applied to an outside fitted camera connectable to theocular optical system of the 26th embodiment. In this formation, thelens system 343 or 361 is replaced with the ocular optical system 324.

The optical system after the transmitting optical system combiningutilizing the pupil division in the objective optical system andutilizing the eccentric optical system can be selected either to havethe ocular optical system and optical visual field direction switchingmeans or to have none.

In the case of either utilizing the pupil division in the objectiveoptical system of the present invention or utilizing the eccentricoptical system, when the means of intercepting the rays other than inthe required visual field direction are provided near the pupils in therespective visual field directions, even if the transmitting opticalsystem is replaced with the solid state image taking device or imageguide, the visual field direction variable endoscope will be able to berealized.

In the formation shown in FIG. 58A, a pupil switching apparatus 368 isprovided near the pupil formed in the light path of the objectiveoptical system 370 consisting of the front side lens group which is thesame as the front side lens group 329a of the 26th embodiment and therear side lens system 348 and a solid state image taking device 369 isarranged. The pupil switching apparatus 368 may be a liquid crystalshutter or the like.

Also, in the formation shown in FIG. 58B, an eccentric optical system371 including the same optical system as the front optical system 347cshown in FIG. 50 is utilized.

FIG. 59A is a formation view of an optical system in the plural visualfield direction type endoscope in the 29th embodiment. FIG. 59B is aformation view of an objective optical system made partially common.

The objective optical system in the 29th embodiment is formed of aplurality of lens groups provided for respective visual fields insteadof the objective optical system 322 so that a plurality of images may beformed by these lens groups. The other formations and operations whichare the same as in the 26th embodiment shall bear the same referencenumerals and shall not be explained here.

The objective optical system 373 shown in FIG. 59A is formed of aplurality of (two in the illustrated example) independent lens groups.The relay lens system 323 and ocular optical system 324 are arranged inthe rear of the objective optical system 373. By the way, the relay lenssystem 323 and ocular optical system may be replaced with an imageforming optical system and solid state image taking device.

The objective optical system 373 may be formed of an independent opticalsystem as in FIG. 59A and may have a part, that is, the prism on thedistal end side made common as in the objective optical system 373'shown in FIG. 59B.

The plurality of images I31 and I32 formed by the objective opticalsystem are transmitted rearward by the relay lens system 323 as atransmitting optical system. In the formation having the ocular opticalsystem 324, as in FIG. 59A, the observer can simultaneously see therespective visual field directions with the eye placed in the pupilposition 374.

On the other hand, in the formation of the image forming optical systemand solid state image taking device, the plurality of images made in therear of the relay lens system 323 are formed on one solid state imagetaking device by the image forming lens. The effect by this formationcan be technically comparatively easily realized by any optical systemafter the objective optical system and transmitting optical system.

By the way, in this embodiment, images may be formed on a plurality ofsolid state image taking devices with the image forming magnificationmade large and the solid state image taking devices placed in thepositions corresponding to the plurality of images.

The 30th embodiment shall be explained with reference to FIG. 60A. Asshown in FIG. 60A, in the optical system of this embodiment, an image isformed on the solid state image taking device 370 through the lenssystem 343 which is arranged in the rear of the relay lens system 342and whereby the light once formed as an image by the relay lens system342 and then made dispersed beams in the respective visual fielddirections is made parallel with the optical axes of the relay lenssystem 342 and optical systems arranged along two optical axes in therear of this lens system 343.

Multiple relay systems by the lens systems 371 and 372 are arrangedalong one optical axis of the two optical axes and an image is formed onthe solid state image taking device 370 by the lens system 372.

Also, multiple relay systems are arranged on the other optical axis.That is to say, the prism 373 for bending the optical axis is arrangednear the pupil formed through the lens system 374 and on the rear sideof this prism 373 are arranged the lens system 374, prism 375, lenssystem 376, prism 377, lens system 378 and mirror 379. The beam isreflected by this mirror 379 arranged at the point P of intersection ofthis optical system and the other optical axis and forms an image on thesolid state image taking device 370 through the lens system 372.

This mirror 379 is rotatable as illustrated. The visual field directioncan be selected by switching to either of the state A indicated by thesolid line and the state B indicated by the dotted line. The otherformations are the same components as are explained in FIG. 49A.

In the inserted section of the rigid endoscope to which this embodimentis applied, the distance between the two optical axes cannot help beingso small as to be several millimeters due to the restriction of theoutside diameter. As the image is formed on one solid state image takingdevice 370 after the lens system 343, in case one optical system is usedthe same as in the relay lens system 342, the beam will diagonallyproject into the solid state image taking device 370 and a color shadingwill be generated. In order to prevent this phenomenon, in thisembodiment, one of the two optical axes is bent by the prisms 373, 375and 377 on the rear side of the lens system 343 as in FIG. 60A so thatthe beams having passed respectively through the two optical axes mayproject vertically onto the image taking surface of the solid stateimage taking device 370 and the generation of the color shading may becontrolled.

FIG. 60B shows a formation of a modification of FIG. 60A. The opticalsystem in FIG. 60A is formed of expanded lens systems 374', 376' and378' expanding respectively the lens systems 374, 376 and 378 so thatthe image may be observed in a larger picture surface size with one ofthe optical systems having two visual field directions. When theformation is separated into the inserted section 380 and the cameraadapter section 381 rotatably fitted to this inserted section 380 andthe camera adapter section 381 is rotatably formed, the picture sizes inthe respective visual field directions will be able to be selectivelymade large.

FIG. 61A shows the 31st embodiment. In this embodiment, objectiveoptical systems 391 and 391' to be a pair on the respective optical axesseparated by a distance D are provided on the distal end side of theinserted section 390 and the respective images by the optical objectivesystems 391 and 391' are transmitted to the rear side respectively bythe relay optical systems 392 and 392'.

The image transmitted by the relay optical system 392 is formed on thesolid state image taking device 370 by the multiple relay opticalsystems comprising the lens systems 371 and 372 the same as in FIG. 60A.

Also, the image transmitted by the relay optical system 392' is formedon the solid state image taking device 370 through the same relaysystems as in FIG. 60A, that is, the multiple relay systems by the prism373, lens system-374, prism 375, lens system 376, prism 377, lens system378, mirror 379 and lens system 372.

The same as in the embodiment in FIG. 60A, as a means of switching thetwo optical systems, a mirror 379 is provided at the point P at whichthe two optical axes intersect with each other. The visual fielddirection can be selected by this mirror 379.

In the modification shown in FIG. 61B, the lens systems 374, 376 and 378forming the relay systems in FIG. 61A are formed respectively of theexpanded lens systems 374', 376' and 378' so that one optical system,that is, the objective optical system 391' and relay optical system 392'of the two optical systems arranged within the inserted section 390 maybe made thinner, the outside diameter of the inserted section may bemade smaller and the insertability may be improved.

Also, when the formation is separated into the inserted section 390 andthe camera adapter section 393 rotatably fitted to the rear end of thisinserted section and the camera adapter section 393 is rotatably formed,the picture size will be able to be selectively varied.

By the way, the present invention is not limited to these embodimentsand modifications and any embodiment or modification formed by combiningparts of them belongs to the present invention.

                  TABLE 1                                                         ______________________________________                                        Lens data of the first embodiment                                             ______________________________________                                         r1 = ∞                                                                             d1 = 0.400  n1 = 1.7682                                                                               ν1 = 71.8                               r2 = ∞                                                                             d2 = 0.300                                                         r3 = 2.4658                                                                              d3 = 0.563  n2 = 1.883  ν2 = 40.8                               r4 = 0.7855                                                                              d4 = 0.453                                                         r5 = ∞                                                                             d5 = 0.400  n3 = 1.8061                                                                               ν3 = 40.9                               r6 = ∞ (pupil)                                                                     d6 = 3.340  n4 = 1.8061                                                                               ν4 = 40.9                               r7 = -2.7844                                                                             d7 = 0.300                                                         r8 = -4.5712                                                                             d8 = 0.400  n5 = 1.62004                                                                              ν5 = 36.3                               r9 = 13.1850                                                                             d9 = 0.730  n6 = 1.788  ν6 = 47.4                              r10 = -3.7741                                                                            d10 = 0.300                                                        r11 = 6.2003                                                                             d11 = 1.949  n7 = 1.60311                                                                              ν7 = 60.7                              r12 = -1.6595                                                                            d12 = 0.409  n8 = 1.84666                                                                              ν8 = 23.8                              r13 = -2.4812                                                                            d13 = 0.306                                                        r14 = -2.3688                                                                            d14 = 0.400  n9 = 1.78472                                                                              ν9 = 25.7                              r15 = -82.9824                                                                           d15 = 0.400 n10 = 1.6968                                                                              ν10 = 55.5                              r16 = -7.6931                                                                            d16 = 7.500                                                        r17 = 17.7721                                                                            d17 = 38.862                                                                              n11 = 1.51633                                                                             ν11 = 64.1                              r18 = -8.3001                                                                            d18 = 6.881 n12 = 1.85026                                                                             ν12 = 32.3                              r19 = -24.9616                                                                           d19 = 0.941                                                        r20 = 36.2005                                                                            d20 = 1.000 n13 = 1.8061                                                                              ν13 = 40.9                              r21 = ∞                                                                            d21 = 10.265                                                                              n14 = 1.51633                                                                             ν14 = 64.1                              r22 = ∞                                                                            d22 = 1.000 n15 = 1.8061                                                                              ν15 = 40.9                              r23 = -36.2005                                                                           d23 = 0.914                                                        r24 = 24.9616                                                                            d24 = 6.881 n16 = 1.85026                                                                             ν16 = 32.3                              r25 = 8.3001                                                                             d25 = 38.862                                                                              n17 = 1.51633                                                                             ν17 = 64.1                              r26 = -17.7721                                                                           d26 = 10.000                                                       r27 = 17.7721                                                                            d27 = 38.862                                                                              n18 = 1.51633                                                                             ν18 = 64.1                              r28 = -8.3001                                                                            d28 = 6.881 n19 = 1.85026                                                                             ν19 = 32.3                              r29 = -24.9616                                                                           d29 = 0.914                                                        r30 = 36.2005                                                                            d30 = 1.000 n20 = 1.8061                                                                              ν20 = 40.9                              r31 = ∞                                                                            d31 = 10.265                                                                              n21 = 1.51633                                                                             ν21 = 64.1                              r32 = ∞                                                                            d32 = 1.000 n22 = 1.8061                                                                              ν22 = 40.9                              r33 = -36.2005                                                                           d33 = 0.914                                                        r34 = 24.9616                                                                            d34 = 6.881 n23 = 1.85026                                                                             ν23 = 32.3                              r35 = 8.3001                                                                             d35 = 38.862                                                                              n24 = 1.51633                                                                             ν24 = 64.1                              r36 = -17.7721                                                                           d36 = 10.000                                                       r37 = 17.7721                                                                            d37 = 38.862                                                                              n25 = 1.51633                                                                             ν25 = 64.1                              r38 = -8.3001                                                                            d38 = 6.881 n26 = 1.85026                                                                             ν26 = 32.3                              r39 = -24.9616                                                                           d39 = 0.914                                                        r40 = 36.2005                                                                            d40 = 1.000 n27 = 1.8061                                                                              ν27 = 40.9                              r41 = ∞                                                                            d41 = 10.265                                                                              n28 = 1.51633                                                                             ν28 = 64.1                              r42 = ∞                                                                            d42 = 1.000 n29 = 1.8061                                                                              ν29 = 40.9                              r43 = -36.2005                                                                           d43 = 0.914                                                        r44 = 24.9616                                                                            d44 = 6.881 n30 = 1.85026                                                                             ν30 = 32.3                              r45 = 8.3001                                                                             d45 = 38.862                                                                              n31 = 1.51633                                                                             ν31 = 64.1                              r46 = -17.7721                                                                           d46 = 5.000                                                        r47 = ∞ (image position)                                                ______________________________________                                    

                  TABLE 2                                                         ______________________________________                                        Lens data of the third embodiment                                             ______________________________________                                         r1 = ∞                                                                             d1 = 0.400  n1 = 1.7682                                                                               ν1 = 71.8                               r2 = ∞                                                                             d2 = 0.300                                                         r3 = 3.8772                                                                              d3 = 1.527  n2 = 1.883  ν2 = 40.8                               r4 = 0.7999                                                                              d4 = 0.449                                                         r5 = ∞                                                                             d5 = 0.400  n3 = 1.8061                                                                               ν3 = 40.9                               r6 = ∞ (pupil)                                                                     d6 = 2.774  n4 = 1.8061                                                                               ν4 = 40.9                               r7 = -2.6393                                                                             d7 = 0.300                                                         r8 = -4.4440                                                                             d8 = 0.400  n5 = 1.62004                                                                              ν5 = 36.3                               r9 = 13.0243                                                                             d9 = 0.643  n6 = 1.788  ν6 = 47.4                              r10 = -3.4953                                                                            d10 = 0.300                                                        r11 = 6.6459                                                                             d11 = 1.858  n7 = 1.60311                                                                              ν7 = 60.7                              r12 = -1.6646                                                                            d12 = 0.416  n8 = 1.84666                                                                              ν8 = 23.8                              r13 = -2.4857                                                                            d13 = 0.300                                                        r14 = -2.4171                                                                            d14 = 0.400  n9 = 1.78472                                                                              ν9 = 25.7                              r15 = -5.1842                                                                            d15 = 0.400 n10 = 1.6968                                                                              ν10 = 55.5                              r16 = -5.8028                                                                            d16 = 7.500                                                        r17 = 17.0269                                                                            d17 = 39.876                                                                              n11 = 1.51633                                                                             ν11 = 64.1                              r18 = -9.1442                                                                            d18 = 6.480 n12 = 1.85026                                                                             ν12 = 32.3                              r19 = -25.2664                                                                           d19 = 0.300                                                        r20 = 38.6357                                                                            d20 = 1.000 n13 = 1.8061                                                                              ν13 = 40.9                              r21 = ∞                                                                            d21 = 10.000                                                                              n14 = 1.51633                                                                             ν14 = 64.1                              r22 = ∞                                                                            d22 = 1.000 n15 = 1.8061                                                                              ν15 = 40.9                              r23 = -38.6357                                                                           d23 = 0.300                                                        r24 = 25.2664                                                                            d24 = 6.480 n16 = 1.85026                                                                             ν16 = 32.3                              r25 = 9.1442                                                                             d25 = 39.876                                                                              n17 = 1.51633                                                                             ν17 = 64.1                              r26 = -17.0269                                                                           d26 = 10.000                                                       r27 = 17.0269                                                                            d27 = 39.876                                                                              n18 = 1.51633                                                                             ν18 = 64.1                              r28 = -9.1442                                                                            d28 = 6.480 n19 = 1.85026                                                                             ν19 = 32.3                              r29 = -25.2664                                                                           d29 = 0.300                                                        r30 = 38.6357                                                                            d30 = 1.000 n20 = 1.8061                                                                              ν20 = 40.9                              r31 = ∞                                                                            d31 = 10.000                                                                              n21 = 1.51633                                                                             ν21 = 64.1                              r32 = ∞                                                                            d32 = 1.000 n22 = 1.8061                                                                              ν22 = 40.9                              r33 = -38.6357                                                                           d33 = 0.300                                                        r34 = 25.2664                                                                            d34 = 6.480 n23 = 1.85026                                                                             ν23 = 32.3                              r35 = 9.1442                                                                             d35 = 39.876                                                                              n24 = 1.51633                                                                             ν24 = 64.1                              r36 = -17.0269                                                                           d36 = 10.000                                                       r37 = 17.0269                                                                            d37 = 39.876                                                                              n25 = 1.51633                                                                             ν25 = 64.1                              r38 = -9.1442                                                                            d38 = 6.480 n26 = 1.85026                                                                             ν26 = 32.3                              r39 = -25.2664                                                                           d39 = 0.300                                                        r40 = 38.6357                                                                            d40 = 1.000 n27 = 1.8061                                                                              ν27 = 40.9                              r41 = ∞                                                                            d41 = 10.000                                                                              n28 = 1.51633                                                                             ν28 = 64.1                              r42 = ∞                                                                            d42 = 1.000 n29 = 1.8061                                                                              ν29 = 40.9                              r43 = -38.6357                                                                           d43 = 0.300                                                        r44 = 25.2664                                                                            d44 = 6.480 n30 = 1.85026                                                                             ν30 = 32.3                              r45 = 9.1442                                                                             d45 = 39.876                                                                              n31 = 1.51633                                                                             ν31 = 64.1                              r46 = -17.0269                                                                           d46 = 5.001                                                        r47 = ∞ (image position)                                                ______________________________________                                    

                  TABLE 3                                                         ______________________________________                                        Lens data of the forth embodiment                                             ______________________________________                                         r1 = ∞                                                                             d1 = 0.400  n1 = 1.7682                                                                               ν1 = 71.8                               r2 = ∞                                                                             d2 = 0.300                                                         r3 = 2.6660                                                                              d3 = 1.000  n2 = 1.883  ν2 = 40.8                               r4 = 0.6568                                                                              d4 = 0.465                                                         r5 = ∞                                                                             d5 = 0.400  n3 = 1.883  ν3 = 40.8                               r6 = ∞ (pupil)                                                                     d6 = 2.938  n4 = 1.883  ν4 = 40.8                               r7 = -2.9259                                                                             d7 = 0.300                                                         r8 = -10.3818                                                                            d8 = 0.400  n5 = 1.62004                                                                              ν5 = 36.3                               r9 = 15.1216                                                                             d9 = 0.562  n6 = 1.788  ν6 = 47.4                              r10 = -4.9186                                                                            d10 = 0.300                                                        r11 = 6.1372                                                                             d11 = 1.797  n7 = 1.618  ν7 = 63.4                              r12 = -1.8144                                                                            d12 = 1.075  n8 = 1.84666                                                                              ν8 = 23.8                              r13 = -2.6860                                                                            d13 = 0.300                                                        r14 = -2.2723                                                                            d14 = 0.615  n9 = 1.78472                                                                              ν9 = 25.7                              r15 = -14.0716                                                                           d15 = 0.437 n10 = 1.6968                                                                              ν10 = 55.5                              r16 = -4.9749                                                                            d16 = 7.500                                                        r17 = 18.4320                                                                            d17 = 37.230                                                                              n11 = 1.51633                                                                             ν11 = 64.1                              r18 = -8.3411                                                                            d18 = 6.671 n12 = 1.85026                                                                             ν12 = 32.3                              r19 = -24.0584                                                                           d19 = 0.300                                                        r20 = 36.1875                                                                            d20 = 1.000 n13 = 1.8061                                                                              ν13 = 40.9                              r21 = ∞                                                                            d21 = 10.000                                                                              n14 = 1.51633                                                                             ν14 = 64.1                              r22 = ∞                                                                            d22 = 1.000 n15 = 1.8061                                                                              ν15 = 40.9                              r23 = -36.1875                                                                           d23 = 0.300                                                        r24 = 24.0584                                                                            d24 = 6.671 n16 = 1.85026                                                                             ν16 = 32.3                              r25 = 8.3411                                                                             d25 = 37.230                                                                              n17 = 1.51633                                                                             ν17 = 64.1                              r26 = -18.4320                                                                           d26 = 10.000                                                       r27 = 18.4320                                                                            d27 = 37.230                                                                              n18 = 1.51633                                                                             ν18 = 64.1                              r28 = -8.3411                                                                            d28 = 6.671 n19 = 1.85026                                                                             ν19 = 32.3                              r29 = -24.0584                                                                           d29 = 0.300                                                        r30 = 36.1875                                                                            d30 = 1.000 n20 = 1.8061                                                                              ν20 = 40.9                              r31 = ∞                                                                            d31 = 10.000                                                                              n21 = 1.51633                                                                             ν21 = 64.1                              r32 = ∞                                                                            d32 = 1.000 n22 = 1.8061                                                                              ν22 = 40.9                              r33 = -36.1875                                                                           d33 = 0.300                                                        r34 = 24.0584                                                                            d34 = 6.671 n23 = 1.85026                                                                             ν23 = 32.3                              r35 = 8.3411                                                                             d35 = 37.230                                                                              n24 = 1.51633                                                                             ν24 = 64.1                              r36 = -18.4320                                                                           d36 = 10.000                                                       r37 = 18.4320                                                                            d37 = 37.230                                                                              n25 = 1.51633                                                                             ν25 = 64.1                              r38 = -8.3411                                                                            d38 = 6.671 n26 = 1.85026                                                                             ν26 = 32.3                              r39 = -24.0584                                                                           d39 = 0.300                                                        r40 = 36.1875                                                                            d40 = 1.000 n27 = 1.8061                                                                              ν27 = 40.9                              r41 = ∞                                                                            d41 = 10.000                                                                              n28 = 1.51633                                                                             ν28 = 64.1                              r42 = ∞                                                                            d42 = 1.000 n29 = 1.8061                                                                              ν29 = 40.9                              r43 = -36.1875                                                                           d43 = 0.300                                                        r44 = 24.0584                                                                            d44 = 6.671 n30 = 1.85026                                                                             ν30 = 32.3                              r45 = 8.3411                                                                             d45 = 37.230                                                                              n31 = 1.51633                                                                             ν31 = 64.1                              r46 = -18.4320                                                                           d46 = 5.000                                                        r47 = ∞                                                                            d47 = 6.000 (reflection plane)                                     r48 = ∞                                                                            d47 = 9.000 (reflection plane)                                     r49 = -15.7631                                                                           d49 = 4.949 n32 = 1.816 ν32 = 46.6                              r50 = -8.9021                                                                            d50 = 2.525                                                        r51 = 9.9691                                                                             d51 = 4.480 n33 = 1.72916                                                                             ν33 = 54.7                              r52 = -16.7003                                                                           d52 = 2.578 n34 = 1.7552                                                                              ν34 = 27.5                              r53 = 4.2972                                                                             d53 = 3.722                                                        r54 = 52.6411                                                                            d54 = 1.000 n35 = 1.5927                                                                              ν35 = 35.3                              r55 = 117.6536                                                                           d55 = 7.067 n36 = 1.618 ν36 = 63.4                              r56 = -77.9950                                                                           d56 = 1.037                                                        r57 = 8.7799                                                                             d57 = 7.000 n37 = 1.72916                                                                             ν37 = 54.7                              r58 = 13.9542                                                                            d58 = 49.995                                                       r59 = ∞ (image position)                                                ______________________________________                                    

                  TABLE 4                                                         ______________________________________                                        Lens data of the fifth embodiment                                             ______________________________________                                         r1 = ∞                                                                             d1 = 0.400  n1 = 1.7682                                                                               ν1 = 71.8                               r2 = ∞                                                                             d2 = 0.300                                                         r3 = 2.8586                                                                              d3 = 1.000  n2 = 1.883  ν2 = 40.8                               r4 = 0.7279                                                                              d4 = 0.466                                                         r5 = ∞                                                                             d5 = 0.400  n3 = 1.883  ν3 = 40.8                               r6 = ∞ (pupil)                                                                     d6 = 2.216  n4 = 1.883  ν4 = 40.8                               r7 = -2.9043                                                                             d7 = 0.300                                                         r8 = -5.6042                                                                             d8 = 0.400  n5 = 1.62004                                                                              ν5 = 36.3                               r9 = 5.6154                                                                              d9 = 0.888  n6 = 1.788  ν6 = 47.4                              r10 = -3.6606                                                                            d10 = 0.300                                                        r11 = 7.1344                                                                             d21 = 1.764  n7 = 1.618  ν7 = 63.4                              r12 = -1.7751                                                                            d12 = 0.597  n8 = 1.84666                                                                              ν8 = 23.8                              r13 = -2.5646                                                                            d13 = 0.302                                                        r14 = -2.1629                                                                            d14 = 0.400  n9 = 1.78472                                                                              ν9 = 25.7                              r15 = -4.7832                                                                            d15 = 0.400 n10 = 1.6968                                                                              ν10 = 55.5                              r16 = -3.9862                                                                            d16 = 7.500                                                        r17 = 18.1763                                                                            d17 = 37.730                                                                              n11 = 1.51633                                                                             ν11 = 64.1                              r18 = -8.5520                                                                            d18 = 6.670 n12 = 1.85026                                                                             ν12 = 32.2                              r19 = -23.4978                                                                           d19 = 0.300                                                        r20 = 39.1240                                                                            d20 = 1.000 n13 = 1.8061                                                                              ν13 = 40.9                              r21 = ∞                                                                            d21 = 10.000                                                                              n14 = 1.51633                                                                             ν14 = 64.1                              r22 = ∞                                                                            d22 = 1.000 n15 = 1.8061                                                                              ν15 = 40.9                              r23 = -39.1240                                                                           d23 = 0.300                                                        r24 = 23.4978                                                                            d24 = 6.670 n16 = 1.85026                                                                             ν16 = 32.2                              r25 = 8.5520                                                                             d25 = 37.730                                                                              n17 = 1.51633                                                                             ν17 = 64.1                              r26 = -18.1763                                                                           d26 = 10.000                                                       r27 = 18.1763                                                                            d27 = 37.730                                                                              n18 = 1.51633                                                                             ν18 = 64.1                              r28 = -8.5520                                                                            d28 = 6.670 n19 = 1.85026                                                                             ν19 = 32.2                              r29 = -23.4978                                                                           d29 = 0.300                                                        r30 = 39.1240                                                                            d30 = 1.000 n20 = 1.8061                                                                              ν20 = 40.9                              r31 = ∞                                                                            d31 = 10.000                                                                              n21 = 1.51633                                                                             ν21 = 64.1                              r32 = ∞                                                                            d32 = 1.000 n22 = 1.8061                                                                              ν22 = 40.9                              r33 = -39.1240                                                                           d33 = 0.300                                                        r34 = 23.4978                                                                            d34 = 6.670 n23 = 1.85026                                                                             ν23 = 32.2                              r35 = 8.5520                                                                             d35 = 37.730                                                                              n24 = 1.51633                                                                             ν24 = 64.1                              r36 = -18.1763                                                                           d36 = 10.000                                                       r37 = 18.1763                                                                            d37 = 37.730                                                                              n25 = 1.51633                                                                             ν25 = 64.1                              r38 = -8.5520                                                                            d38 = 6.670 n26 = 1.85026                                                                             ν26 = 32.2                              r39 = -23.4978                                                                           d39 = 0.300                                                        r40 = 39.1240                                                                            d40 = 1.000 n27 = 1.8061                                                                              ν27 = 40.9                              r41 = ∞                                                                            d41 = 10.000                                                                              n28 = 1.51633                                                                             ν28 = 64.1                              r42 = ∞                                                                            d42 = 1.000 n29 = 1.8061                                                                              ν29 = 40.9                              r43 = -39.1240                                                                           d43 = 0.300                                                        r44 = 23.4978                                                                            d44 = 6.670 n30 = 1.85026                                                                             ν30 = 32.2                              r45 = 8.5520                                                                             d45 = 37.730                                                                              n31 = 1.51633                                                                             ν31 = 64.1                              r46 = -18.1763                                                                           d46 = 15.000                                                       r47 = -15.9408                                                                           d47 = 7.000 n32 = 1.816 ν32 = 46.6                              r48 = -10.5614                                                                           d48 = 1.898                                                        r49 = 20.0434                                                                            d49 = 1.000 n33 = 1.72916                                                                             ν33 = 54.7                              r50 = 11.2226                                                                            d50 = 1.852 n34 = 1.7552                                                                              ν34 = 27.5                              r51 = 8.3607                                                                             d51 = 6.099                                                        r52 = -24.1926                                                                           d52 = 3.535 n35 = 1.5927                                                                              ν35 = 35.3                              r53 = 9.6335                                                                             d53 = 9.958 n36 = 1.618 ν36 = 63.4                              r54 = -27.0337                                                                           d54 = 0.300                                                        r55 = 22.5105                                                                            d55 = 7.000 n37 = 1.72916                                                                             ν37 = 54.7                              r56 = 317.0029                                                                           d56 = 102.172                                                      r57 = ∞ (image position)                                                ______________________________________                                    

                  TABLE 5                                                         ______________________________________                                        Lens data of the sixth embodiment                                             ______________________________________                                         r1 = ∞                                                                             d1 = 0.400  n1 = 1.7682                                                                               ν1 = 71.8                               r2 = ∞                                                                             d2 = 0.300                                                         r3 = 2.5311                                                                              d3 = 1.000  n2 = 1.883  ν2 = 40.8                               r4 = 0.6002                                                                              d4 = 0.483                                                         r5 = ∞                                                                             d5 = 0.492  n3 = 1.883  ν3 = 40.8                               r6 = ∞ (pupil)                                                                     d6 = 2.925  n4 = 1.883  ν4 = 40.8                               r7 = -2.9244                                                                             d7 = 0.300                                                         r8 = -20.1110                                                                            d8 = 0.500  n5 = 1.62004                                                                              ν5 = 36.3                               r9 = 10.9637                                                                             d9 = 0.607  n6 = 1.788  ν6 = 47.4                              r10 = -6.2777                                                                            d10 = 0.300                                                        r11 = 6.1192                                                                             d11 = 1.860  n7 = 1.618  ν7 = 63.4                              r12 = -1.8981                                                                            d12 = 0.810  n8 = 1.84666                                                                              ν8 = 23.8                              r13 = -2.7109                                                                            d13 = 0.302                                                        r14 = -2.2811                                                                            d14 = 0.400  n9 = 1.78472                                                                              ν9 = 25.7                              r15 = -13.8892                                                                           d15 = 1.289 n10 = 1.6968                                                                              ν10 = 55.5                              r16 = -5.4300                                                                            d16 = 7.500                                                        r17 = 18.4228                                                                            d17 = 37.662                                                                              n11 = 1.51633                                                                             ν11 = 64.1                              r18 = -8.3677                                                                            d18 = 6.665 n12 = 1.85026                                                                             ν12 = 32.3                              r19 = -24.4094                                                                           d19 = 0.300                                                        r20 = 35.7941                                                                            d20 = 1.000 n13 = 1.8061                                                                              ν13 = 40.9                              r21 = ∞                                                                            d21 = 10.000                                                                              n14 = 1.51633                                                                             ν14 = 64.1                              r22 = ∞                                                                            d22 = 1.000 n15 = 1.8061                                                                              ν15 = 40.9                              r23 = -35.7941                                                                           d23 = 0.300                                                        r24 = 24.4094                                                                            d24 = 6.665 n16 = 1.85026                                                                             ν16 = 32.3                              r25 = 8.3677                                                                             d25 = 37.662                                                                              n17 = 1.51633                                                                             ν17 = 64.1                              r26 = -18.4228                                                                           d26 = 10.000                                                       r27 = 18.4228                                                                            d27 = 37.662                                                                              n18 = 1.51633                                                                             ν18 = 64.1                              r28 = -8.3677                                                                            d28 = 6.665 n19 = 1.85026                                                                             ν19 = 32.3                              r29 = -24.4094                                                                           d29 = 0.300                                                        r30 = 35.7941                                                                            d30 = 1.000 n20 = 1.8061                                                                              ν20 = 40.9                              r31 = ∞                                                                            d31 = 10.000                                                                              n21 = 1.51633                                                                             ν21 = 64.1                              r32 = ∞                                                                            d32 = 1.000 n22 = 1.8061                                                                              ν22 = 40.9                              r33 = -35.7941                                                                           d33 = 0.300                                                        r34 = 24.4094                                                                            d34 = 6.665 n23 = 1.85026                                                                             ν23 = 32.3                              r35 = 8.3677                                                                             d35 = 37.662                                                                              n24 = 1.51633                                                                             ν24 = 64.1                              r36 = -18.4228                                                                           d36 = 10.000                                                       r37 = 18.4228                                                                            d37 = 37.662                                                                              n25 = 1.51633                                                                             ν25 = 64.1                              r38 = -8.3677                                                                            d38 = 6.665 n26 = 1.85026                                                                             ν26 = 32.3                              r39 = -24.4094                                                                           d39 = 0.300                                                        r40 = 35.7941                                                                            d40 = 1.000 n27 = 1.8061                                                                              ν27 = 40.9                              r41 = ∞                                                                            d41 = 10.000                                                                              n28 = 1.51633                                                                             ν28 = 64.1                              r42 = ∞                                                                            d42 = 1.000 n29 = 1.8061                                                                              ν29 = 40.9                              r43 = -35.7941                                                                           d43 = 0.300                                                        r44 = 24.4094                                                                            d44 = 6.665 n30 = 1.85026                                                                             ν30 = 32.3                              r45 = 8.3677                                                                             d45 = 37.662                                                                              n31 = 1.51633                                                                             ν31 = 64.1                              r46 = -18.4228                                                                           d46 = 5.000                                                        r47 = ∞                                                                            d47 = 11.000                                                       r48 = -10.3813                                                                           d48 = 5.655 n32 = 1.816 ν32 = 46.6                              r49 = -8.8890                                                                            d49 = 0.483                                                        r50 = 7.4696                                                                             d50 = 3.769 n33 = 1.72916                                                                             ν33 = 54.7                              r51 = 181.6429                                                                           d51 = 2.093 n34 = 1.7552                                                                              ν34 = 27.5                              r52 = 4.4460                                                                             d52 = 3.047                                                        r53 = -30.7603                                                                           d53 = 1.001 n35 = 1.5927                                                                              ν35 = 353                               r54 = 41.5845                                                                            d54 = 1.706 n36 = 1.618 ν36 = 63.4                              r55 = -17.8259                                                                           d55 = 0.342                                                        r56 = 7.9775                                                                             d56 = 5.749 n37 = 1.72916                                                                             ν37 = 54.7                              r57 = 12.6259                                                                            d57 = 39.986                                                       r58 = ∞ (image position)                                                ______________________________________                                    

                  TABLE 6                                                         ______________________________________                                        Lens data of the tenth embodiment                                             ______________________________________                                         r1 = ∞                                                                             d1 = 0.400  n1 = 1.7682                                                                               ν1 = 71.8                               r2 = ∞                                                                             d2 = 0.500                                                         r3 = -15.1509                                                                            d3 = 0.500  n2 = 1.883  ν2 = 40.8                               r4 = 1.8541                                                                              d4 = 0.400                                                         r5 = ∞                                                                             d5 = 1.471  n3 = 1.8061                                                                               ν3 = 40.9                               r6 = ∞ (pupil)                                                                     d6 = 8.000  n4 = 1.8061                                                                               ν4 = 40.9                               r7 = -6.3400                                                                             d7 = 0.300                                                         r8 = 29.8778                                                                             d8 = 6.980  n5 = 1.60311                                                                              ν5 = 60.7                               r9 = -76.5455                                                                            d9 = 2.000                                                        r10 = 11.8863                                                                            d10 = 12.000                                                                               n6 = 1.60311                                                                              ν6 = 60.7                              r11 = -14.2286                                                                           d11 = 1.000  n7 = 1.84666                                                                              ν7 = 23.8                              r12 = 6.6719                                                                             d12 = 1.327                                                        r13 = 16.2399                                                                            d13 = 1.000  n8 = 1.84666                                                                              ν8 = 23.8                              r14 = 6.8781                                                                             d14 = 2.641  n9 = 1.60311                                                                              ν9 = 60.7                              r15 = -16.3999                                                                           d15 = 0.300                                                        r16 = 9.6243                                                                             d16 = 2.045 n10 = 1.72916                                                                             ν10 = 54.7                              r17 = 42.1473                                                                            d17 = 12.000                                                       r18 = 20.3224                                                                            d18 = 28.648                                                                              n11 = 1.51633                                                                             ν11 = 64.1                              r19 = -9.1270                                                                            d19 = 1.000 n12 = 1.85026                                                                             ν12 = 32.3                              r20 = -17.5105                                                                           d20 = 0.300                                                        r21 = 37.3211                                                                            d21 = 2.038 n13 = 1.8061                                                                              ν13 = 40.9                              r22 = ∞                                                                            d22 = 25.393                                                                              n14 = 1.51633                                                                             ν14 = 64.1                              r23 = ∞                                                                            d23 = 2.038 n15 = 1.8061                                                                              ν15 = 40.9                              r24 = -37.3211                                                                           d24 = 0.300                                                        r25 = 17.5105                                                                            d25 = 1.000 n16 = 1.85026                                                                             ν16 = 32.3                              r26 = 9.1270                                                                             d26 = 28.648                                                                              n17 = 1.51633                                                                             ν17 = 64.1                              r27 = -20.3224                                                                           d27 = 14.000                                                       r28 = 20.3224                                                                            d28 = 28.648                                                                              n18 = 1.51633                                                                             ν18 = 64.1                              r29 = -9.1270                                                                            d29 = 1.000 n19 = 1.85026                                                                             ν19 = 32.3                              r30 = -17.5105                                                                           d30 = 0.300                                                        r31 = 37.3211                                                                            d31 = 2.038 n20 = 1.8061                                                                              ν20 = 40.9                              r32 = ∞                                                                            d32 = 25.393                                                                              n21 = 1.51633                                                                             ν21 = 64.1                              r33 = ∞                                                                            d33 = 2 038 n22 = 1.8061                                                                              ν22 = 40.9                              r34 = -37.3211                                                                           d34 = 0.300                                                        r35 = 17.5105                                                                            d35 = 1.000 n23 = 1.85026                                                                             ν23 = 32.3                              r36 = 9.1270                                                                             d36 = 28.648                                                                              n24 = 1.51633                                                                             ν24 = 64.1                              r37 = -20.3224                                                                           d37 = 14.000                                                       r38 = 20.3224                                                                            d38 = 28.648                                                                              n25 = 1.51633                                                                             ν25 = 64.1                              r39 = -9.1270                                                                            d39 = 1.000 n26 = 1.85026                                                                             ν26 = 32.3                              r40 = -17.5105                                                                           d40 = 0.300                                                        r41 = 37.3211                                                                            d41 = 2.038 n27 = 1.8061                                                                              ν27 = 40.9                              r42 = ∞                                                                            d42 = 25.393                                                                              n28 = 1.51633                                                                             ν28 = 64.1                              r43 = ∞                                                                            d43 = 2.038 n29 = 1.8061                                                                              ν29 = 40.9                              r44 = -37.3211                                                                           d44 = 0.300                                                        r45 = 17.5105                                                                            d45 = 1.000 n30 = 1.85026                                                                             ν30 = 32.3                              r46 = 9.1270                                                                             d46 = 28.648                                                                              n31 = 1.51633                                                                             ν31 = 64.1                              r47 = -20 3224                                                                           d47 = 17.000                                                       r48 = -14.8821                                                                           d48 = 2.846 n32 = 1.72916                                                                             ν32 = 54.7                              r49 = -8.8016                                                                            d49 = 0.300                                                        r50 = 15.1352                                                                            d50 = 4.084 n33 = 1.618 ν33 = 63.4                              r51 = -7.3338                                                                            d51 = 1.000 n34 = 1.5927                                                                              ν34 = 35.3                              r52 = 9.5056                                                                             d52 = 4.000                                                        r53 = -16.8952                                                                           d53 = 2.000 n35 = 1.7552                                                                              ν35 = 27.5                              r54 = -13.2379                                                                           d54 = 2.000 n36 = 1.72916                                                                             ν36 = 54.7                              r55 = -23.2387                                                                           d55 = 0.300                                                        r56 = 22.9913                                                                            d56 = 2.000 n37 = 1.816 ν37 = 46.6                              r57 = 89.7162                                                                            d57 = 15.000                                                       r58 = ∞                                                                            d58 = 6.000 (reflection plane)                                     r59 = ∞                                                                            d59 = 4.000 (reflection plane)                                     r60 = 22.5828                                                                            d60 = 1.000 n38 = 1.78472                                                                             ν38 = 25.7                              r61 = 6.1627                                                                             d61 = 3.276 n39 = 1.55963                                                                             ν39 = 61.2                              r62 = 9.4965                                                                             d62 = 1.747                                                        r63 = 13.6433                                                                            d63 = 3.041 n40 = 1.60311                                                                             ν40 = 60.7                              r64 = -11.6980                                                                           d64 = 29.780                                                       r65 = ∞ (image position)                                                ______________________________________                                    

                  TABLE 9                                                         ______________________________________                                        Lens data of the eleventh embodiment                                          ______________________________________                                         r1 = ∞                                                                             d1 = 0.400  n1 = 1.7682                                                                               ν1 = 71.8                               r2 = ∞                                                                             d2 = 0.500                                                         r3 = -27.1944                                                                            d3 = 0.500  n2 = 1.883  ν2 = 40.8                               r4 = 1.6149                                                                              d4 = 0.400                                                         r5 = ∞                                                                             d5 = 0.648  n3 = 1.8061                                                                               ν3 = 40.9                               r6 = ∞ (pupil)                                                                     d6 = 8.000  n4 = 4.8061                                                                               ν4 = 40.9                               r7 = -5.9410                                                                             d7 = 0.300                                                         r8 = 34.5218                                                                             d8 = 1.405  n5 = 1.60311                                                                              ν5 = 60.7                               r9 = -44.4283                                                                            d9 = 1.636                                                        r10 = 10.5798                                                                            d10 = 11.910                                                                               n6 = 1.60311                                                                              ν6 = 60.7                              r11 = -9.6402                                                                            d11 = 1.000  n7 = 1.84666                                                                              ν7 = 23.8                              r12 = 5.5533                                                                             d12 = 1.354                                                        r13 = 16.9402                                                                            d13 = 1.000  n8 = 1.84666                                                                              ν8 = 23.8                              r14 = 5.6237                                                                             d14 = 2.775  n9 = 1.60311                                                                              ν9 = 60.7                              r15 = -11.8857                                                                           d15 = 0.300                                                        r16 = 9.6717                                                                             d16 = 2.054 n10 = 1.72916                                                                             ν10 = 54.7                              r17 = 67.8305                                                                            d17 = 12.000                                                       r18 = 19.4101                                                                            d18 = 30.497                                                                              n11 = 1.51633                                                                             ν11 = 64.1                              r19 = -9.3708                                                                            d19 = 1.000 n12 = 1.85026                                                                             ν12 = 32.3                              r20 = -18.4223                                                                           d20 = 0.300                                                        r21 = 37.3503                                                                            d21 = 1.000 n13 = 1.8061                                                                              ν13 = 40.9                              r22 = ∞                                                                            d22 = 29.679                                                                              n14 = 1.51633                                                                             ν14 = 64.1                              r23 = ∞                                                                            d23 = 1.000 n15 = 1.8061                                                                              ν15 = 40.9                              r24 = -37.3503                                                                           d24 = 0.300                                                        r25 = 18.4223                                                                            d25 = 1.000 n16 = 1.8.5026                                                                            ν16 = 32.3                              r26 = 9.3708                                                                             d26 = 30.497                                                                              n17 = 1.51633                                                                             ν17 = 64.1                              r27 = -19.4101                                                                           d27 = 14.000                                                       r28 = 19.4101                                                                            d28 = 30.497                                                                              n18 = 1.51633                                                                             ν18 = 64.1                              r29 = -9.3708                                                                            d29 = 1.000 n19 = 1.85026                                                                             ν19 = 32.3                              r30 = -18.4223                                                                           d30 = 0.300                                                        r31 = 37.3503                                                                            d31 = 1.000 n20 = 1.8061                                                                              ν20 = 40.9                              r32 = ∞                                                                            d32 = 29.679                                                                              n21 = 1.51633                                                                             ν21 = 64.1                              r33 = ∞                                                                            d33 = 1.000 n22 = 1.8061                                                                              ν22 = 40.9                              r34 = -37.3503                                                                           d34 = 0.300                                                        r35 = 18.4223                                                                            d35 = 1.000 n23 = 1.85026                                                                             ν23 = 32.3                              r36 = 9.3708                                                                             d36 = 30.497                                                                              n24 = 1.51633                                                                             ν24 = 64.1                              r37 = -19.4101                                                                           d37 = 14.000                                                       r38 = 19.4101                                                                            d38 = 30.497                                                                              n25 = 1.51633                                                                             ν25 = 64.1                              r39 = -9.3708                                                                            d39 = 1.000 n26 = 1.85026                                                                             ν26 = 32.3                              r40 = -18.4223                                                                           d40 = 0.300                                                        r41 = 37.3503                                                                            d41 = 1.000 n27 = 1.8061                                                                              ν27 = 40.9                              r42 = ∞                                                                            d42 = 29.679                                                                              n28 = 1.51633                                                                             ν28 = 64.1                              r43 = ∞                                                                            d43 = 1.000 n29 = 1.8061                                                                              ν29 = 40.9                              r44 = -37.3503                                                                           d44 = 0.300                                                        r45 = 18.4223                                                                            d45 = 1.000 n30 = 1.85026                                                                             ν30 = 32.3                              r46 = 9.3708                                                                             d46 = 30.497                                                                              n31 = 1.51633                                                                             ν31 = 64.1                              r47 = -19.4101                                                                           d47 = 19.000                                                       r48 = -14.3213                                                                           d48 = 7.000 n32 = 1.72916                                                                             ν32 = 54.7                              r49 = -11.0960                                                                           d49 = 0.300                                                        r50 = 33.1140                                                                            d50 = 1.047 n33 = 1.618 ν33 = 63.4                              r51 = 9.1082                                                                             d51 = 7.000 n34 = 1.5927                                                                              ν34 = 35.3                              r52 = 67.5887                                                                            d52 = 3.277                                                        r53 = -9.9528                                                                            d53 = 7.000 n35 = 1.7552                                                                              ν35 = 27.5                              r54 = 41.3894                                                                            d54 = 10.000                                                                              n36 = 1.72916                                                                             ν36 = 54.7                              r55 = -19.8178                                                                           d55 = 3.000                                                        r56 = -63.2683                                                                           d56 = 7.000 n37 = 1.816 ν37 = 46.6                              r57 = -41.6536                                                                           d57 = 6.621                                                        r58 = 20.1426                                                                            d58 = 2.426 n38 = 1.51633                                                                             ν38 = 64.1                              r59 = -122.3553                                                                          d59 = 5.000 n39 = 1.78472                                                                             ν39 = 25.7                              r60 = 32.7733                                                                            d60 = 2.000                                                        r61 = 21.5258                                                                            d61 = 5.000 n40 = 1.5725                                                                              ν40 = 57.8                              r62 = 563.4090                                                                           d62 = 36.001                                                       r63 = ∞ (image position)                                                ______________________________________                                    

                  TABLE 8                                                         ______________________________________                                        Lens data of the twelfth embodiment                                           ______________________________________                                         r1 = ∞                                                                             d1 = 0.400  n1 = 1.7682                                                                               ν1 = 71.8                               r2 = ∞                                                                             d2 = 0.500                                                         r3 = -5.6176                                                                             d3 = 8.000  n2 = 1.883  ν2 = 40.8                               r4 = ∞ (pupil)                                                                     d4 = 8.000  n3 = 1.883  ν3 = 40.8                               r5 = -10.6525                                                                            d5 = 1.727                                                         r6 = 225.1706                                                                            d6 = 1.024  n4 = 1.60311                                                                              ν4 = 60.7                               r7 = 794.5057                                                                            d7 = 0.803                                                         r8 = 7.7627                                                                              d8 = 3.448  n5 = 1.6968                                                                               ν5 = 55.5                               r9 = 7.0551                                                                              d9 = 1.200  n6 = 1.84666                                                                              ν6 = 23.8                              r10 = 6.6689                                                                             d10 = 1.754                                                        r11 = 21.0094                                                                            d11 = 1.000  n7 = 1.84666                                                                              ν7 = 23.8                              r12 = 5.2971                                                                             d12 = 3.637  n8 = 1.60311                                                                              ν8 = 60.7                              r13 = -17.1652                                                                           d13 = 0.300                                                        r14 = 9.0345                                                                             d14 = 2.401  n9 = 1.72916                                                                              ν9 = 54.7                              r15 = 40.5646                                                                            d15 = 12.000                                                       r16 = 19.9468                                                                            d16 = 30.262                                                                              n10 = 1.51633                                                                             ν10 = 64.1                              r17 = -9.0769                                                                            d17 = 1.018 n11 = 1.85026                                                                             ν11 = 32.3                              r18 = -18.5715                                                                           d18 = 0.300                                                        r19 = 34.7626                                                                            d19 = 3.093 n12 = 1.8061                                                                              ν12 = 40.9                              r20 = ∞                                                                            d20 = 19.606                                                                              n13 = 1.51633                                                                             ν13 = 64.1                              r21 = ∞                                                                            d21 = 3.093 n14 = 1.8061                                                                              ν14 = 40.9                              r22 = -34.7626                                                                           d22 = 0.300                                                        r23 = 18.5715                                                                            d23 = 1.018 n15 = 1.85026                                                                             ν15 = 32.3                              r24 = 9.0769                                                                             d24 = 30.262                                                                              n16 = 1.51633                                                                             ν16 = 64.1                              r25 = -19.9468                                                                           d25 = 14.000                                                       r26 = 19.9468                                                                            d26 = 30.262                                                                              n17 = 1.51633                                                                             ν17 = 64.1                              r27 = -9.0769                                                                            d27 = 1.018 n18 = 1.85026                                                                             ν18 = 32.3                              r28 = -18.5715                                                                           d28 = 0.300                                                        r29 = 34.7626                                                                            d29 = 3.093 n19 = 1.8061                                                                              ν19 = 40.9                              r30 = ∞                                                                            d30 = 19.606                                                                              n20 = 1.51633                                                                             ν20 = 64.1                              r31 = ∞                                                                            d31 = 3.093 n21 = 1.8061                                                                              ν21 = 40.9                              r32 = -34.7626                                                                           d32 = 0.300                                                        r33 = 18.5715                                                                            d33 = 1.018 n22 = 1.85026                                                                             ν22 = 32.3                              r34 = 9.0769                                                                             d34 = 30.262                                                                              n23 = 1.51633                                                                             ν23 = 64.1                              r35 = -19.9468                                                                           d35 = 14.000                                                       r36 = 19.9468                                                                            d36 = 30.262                                                                              n24 = 1.51633                                                                             ν24 = 64.1                              r37 = -9.0769                                                                            d37 = 1.018 n25 = 1.85026                                                                             ν25 = 32.3                              r38 = -18.5715                                                                           d38 = 0.300                                                        r39 = 34.7626                                                                            d39 = 3.093 n26 = 1.8061                                                                              ν26 = 40.9                              r40 = ∞                                                                            d40 = 19.606                                                                              n27 = 1.51633                                                                             ν27 = 64.1                              r41 = ∞                                                                            d41 = 3.093 n28 = 1.8061                                                                              ν28 = 40.9                              r42 = -34.7626                                                                           d42 = 0.300                                                        r43 = 18.5715                                                                            d43 = 1.018 n29 = 1.85026                                                                             ν29 = 32.3                              r44 = 9.0769                                                                             d42 = 30.262                                                                              n30 = 1.51633                                                                             ν30 = 64.1                              r45 = -19.9468                                                                           d45 = 19.000                                                       r46 = -11.8408                                                                           d46 = 5.820 n31 = 1.72916                                                                             ν31 = 54.7                              r47 = -9.1946                                                                            d47 = 0.300                                                        r48 = 24.0775                                                                            d48 = 10.000                                                                              n32 = 1.618 ν32 = 63.4                              r49 = -26.2109                                                                           d49 = 7.000 n33 = 1.5927                                                                              ν33 = 35.3                              r50 = 63.4749                                                                            d50 = 3.000                                                        r51 = -8.3204                                                                            d51 = 5.376 n34 = 1.7552                                                                              ν34 = 27.5                              r52 = -38.8722                                                                           d52 = 10.000                                                                              n35 = 1.72916                                                                             ν35 = 54.7                              r53 = -19.1304                                                                           d53 = 3.000                                                        r54 = -83.1506                                                                           d54 = 7.000 n36 = 1.816 ν36 = 46.6                              r55 = -41.8244                                                                           d55 = 8.346                                                        r56 = -26.1283                                                                           d56 = 4.325 n37 = 1.51633                                                                             ν37 = 64.1                              r57 = -7.8805                                                                            d57 = 4.552 n38 = 1.78472                                                                             ν38 = 25.7                              r58 = -14.4880                                                                           d58 = 0.300                                                        r59 = 31.7804                                                                            d59 = 5.000 n39 = 1.5725                                                                              ν39 = 57.8                              r60 = 6326.3883                                                                          d60 = 36.032                                                       r61 = ∞ (image position)                                                ______________________________________                                    

                  TABLE 9                                                         ______________________________________                                        Lens data of the thirteenth embodiment                                        ______________________________________                                         r1 = ∞                                                                             d1 = 0.400  n1 = 1.7682                                                                               ν1 = 71.8                               r2 = ∞                                                                             d2 = 0.500                                                         r3 = 14.7408                                                                             d3 = 0.500  n2 = 1.883  ν2 = 40.8                               r4 = 1.5441                                                                              d4 = 0.400                                                         r5 = ∞                                                                             d5 = 0.572  n3 = 1.8061                                                                               ν3 = 40.9                               r6 = ∞ (pupil)                                                                     d6 = 7.966  n4 = 1.8061                                                                               ν4 = 40.9                               r7 = -5.9996                                                                             d7 = 0.300                                                         r8 = 38.8172                                                                             d8 = 1.360  n5 = 1.60311                                                                              ν5 = 60.7                               r9 = -54.0250                                                                            d9 = 1.040                                                        r10 = 10.8354                                                                            d10 = 11.720                                                                               n6 = 1.60311                                                                              ν6 = 60.7                              r11 = -36.1554                                                                           d11 = 1.000  n7 = 1.84666                                                                              ν7 = 23.8                              r12 = 5.7085                                                                             d12 = 1.444                                                        r13 = 17.6383                                                                            d13 = 1.000  n8 = 1.84666                                                                              ν8 = 23.8                              r14 = 5.3388                                                                             d14 = 3.339  n9 = 1.60311                                                                              ν9 = 60.7                              r15 = -10.4808                                                                           d15 = 0.300                                                        r16 = 10.4139                                                                            d16 = 2.316 n10 = 1.72916                                                                             ν10 = 54.7                              r17 = 1299.7086                                                                          d17 = 12.000                                                       r18 = 20.9531                                                                            d18 = 28.137                                                                              n11 = 1.51633                                                                             ν11 = 64.1                              r19 = -9.0377                                                                            d19 = 1.029 n12 = 1.85026                                                                             ν12 = 32.3                              r20 = -17.1424                                                                           d20 = 0.300                                                        r21 = 37.8341                                                                            d21 = 1.462 n13 = 1.8061                                                                              ν13 = 40.9                              r22 = ∞                                                                            d22 = 26.759                                                                              n14 = 1.51633                                                                             ν14 = 64.1                              r23 = ∞                                                                            d23 = 1.462 n15 = 1.8061                                                                              ν15 = 40.9                              r24 = -37.8341                                                                           d24 = 0.30.0                                                       r25 = 17.1424                                                                            d25 = 1 029 n16 = 1.85026                                                                             ν16 = 32.3                              r26 = 9.0377                                                                             d26 = 28.137                                                                              n17 = 1.51633                                                                             ν17 = 64.1                              r27 = -20.9531                                                                           d27 = 14.000                                                       r28 = 20.9531                                                                            d28 = 28.137                                                                              n18 = 1.51633                                                                             ν18 = 64.1                              r29 = -9.0377                                                                            d29 = 1.029 n19 = 1.85026                                                                             ν19 = 32.3                              r30 = -17.1424                                                                           d30 = 0.300                                                        r31 = 37.8341                                                                            d31 = 1.462 n20 = 1.8061                                                                              ν20 = 40.9                              r32 = ∞                                                                            d32 = 26.759                                                                              n21 = 1.51633                                                                             ν21 = 64.1                              r33 = ∞                                                                            d33 = 1.462 n22 = 1.8061                                                                              ν22 = 40.9                              r34 = -37.8341                                                                           d34 = 0.300                                                        r35 = 17.1424                                                                            d35 = 1.029 n23 = 1.85026                                                                             ν23 = 32.3                              r36 = 9.0377                                                                             d36 = 28.137                                                                              n24 = 1.51633                                                                             ν24 = 64.1                              r37 = -20.9531                                                                           d37 = 14.000                                                       r38 = 20.9531                                                                            d38 = 28.137                                                                              n25 = 1.51633                                                                             ν25 = 64.1                              r39 = -9.0377                                                                            d39 = 1.029 n26 = 1.85026                                                                             ν26 = 32.3                              r40 = -17.1424                                                                           d40 = 0.300                                                        r41 = 37.8341                                                                            d41 = 1.462 n27 = 1.8061                                                                              ν27 = 40.9                              r42 = ∞                                                                            d42 = 26.759                                                                              n28 = 1.51633                                                                             ν28 = 64.1                              r43 = ∞                                                                            d43 = 1.462 n29 = 1.8061                                                                              ν29 = 40.9                              r44 = -37.8341                                                                           d44 = 0.300                                                        r45 = 17.1424                                                                            d45 = 1.029 n30 = 1.85026                                                                             ν30 = 32.3                              r46 = 9.0377                                                                             d46 = 28.137                                                                              n31 = 1.51633                                                                             ν31 = 64.1                              r47 = -20.9531                                                                           d47 = 19.000                                                       r48 = -13.4332                                                                           d48 = 7.000 n32 = 1.72916                                                                             ν32 = 54.7                              r49 = -11.0047                                                                           d49 = 0.300                                                        r50 = 17.1878                                                                            d50 = 5.837 n33 = 1.618 ν33 = 63.4                              r51 = 57.8341                                                                            d51 = 7.000 n34 = 1.5927                                                                              ν34 = 35.3                              r52 = 38.7072                                                                            d52 = 4.174                                                        r53 = -8.1955                                                                            d53 = 6.919 n35 = 1.7552                                                                              ν35 = 27.5                              r54 = 42.2429                                                                            d54 = 10.000                                                                              n36 = 1.72916                                                                             ν36 = 54.7                              r55 = -19.4465                                                                           d55 = 0.300                                                        r56 = 944.8567                                                                           d56 = 4.699 n37 = 1.816,                                                                              ν37 = 46.6                              r57 = -50.3836                                                                           d57 = 18.931                                                       r58 = 136.6914                                                                           d58 = 5.000 n38 = 1.51633                                                                             ν38 = 64.1                              r59 = -21.5686                                                                           d59 = 5.000 n39 = 1.78472                                                                             ν39 = 25.7                              r60 = -47.7722                                                                           d60 = 3.000                                                        r61 = 24.4617                                                                            d61 = 5.000 n40 = 1.5725                                                                              ν40 = 57.8                              r62 = 207.2457                                                                           d62 = 24.000                                                       r63 = ∞ (image position)                                                ______________________________________                                    

                  TABLE 10                                                        ______________________________________                                        Lens data of the twenty third embodiment                                      ______________________________________                                         r1 = ∞                                                                             d1 = 0.4    n1 = 1.769000                                                                             ν1 = 71.8                               r2 = ∞                                                                             d2 = 0.3                                                           r3 = ∞                                                                             d3 = 0.5    n2 = 1.784720                                                                             ν2 = 25.8                               r4 = 2.18120                                                                             d4 = 0.8                                                           r5 = ∞                                                                             d5 = 6.524779                                                                             n3 = 1.806098                                                                             ν3 = 40.9                               r6 = ∞                                                                             d6 = 0.000000                                                                             n4 = 1.806098                                                                             ν4 = 40.9                               r7 = ∞                                                                             d7 = 10.000000                                                                            n5 = 1.806098                                                                             ν5 = 40.9                               r8 = -18.90821                                                                           d8 = 2.000000                                                      r9 = 11.34978                                                                            d9 = 7.000000                                                                             n6 = 1.589130                                                                             ν6 = 61.2                              r10 = -6.85269                                                                           d10 = 7.000000                                                                             n7 = 1.784718                                                                             ν7 = 25.7                              r11 = -9.21315                                                                           d11 = 1.757525                                                     r12 = -5.83605                                                                           d12 = 1.329338                                                                             n8 = 1.784718                                                                             ν8 = 25.7                              r13 = 21.54459                                                                           d13 = 5.000000                                                                             n9 = 1.772499                                                                             ν9 = 49.6                              r14 = -9.87710                                                                           d14 = 0.300000                                                     r15 = 23.34659                                                                           d15 = 5.000000                                                                            n10 = 1.729157                                                                            ν10 = 54.7                              r16 = -46.95906                                                                          d16 = 9.832604                                                     ______________________________________                                    

                  TABLE 11                                                        ______________________________________                                        Lens data of the twenty fourth embodiment                                     ______________________________________                                         r1 = ∞                                                                             d1 = 0.4    n1 = 1.769000                                                                             ν1 = 71.8                               r2 = ∞                                                                             d2 = 0.3                                                           r3 = ∞                                                                             d3 = 0.5    n2 = 1.784720                                                                             ν2 = 25.8                               r4 = 2.24795                                                                             d4 = 0.8                                                           r5 = ∞                                                                             d5 = 26.000000                                                                            n3 = 1.806098                                                                             ν3 = 40.9                               r6 = ∞                                                                             d6 = 0.000000                                                                             n4 = 1.806098                                                                             ν4 = 40.9                               r7 = ∞                                                                             d7 = 28.856575                                                                            n5 = 1.806098                                                                             ν5 = 40.9                               r8 = -36.97230                                                                           d8 = 15.000000                                                     r9 = 10.27055                                                                            d9 = 13.872951                                                                            n6 = 1.496999                                                                             ν6 = 31.6                              r10 = -6.76542                                                                           d10 = 8.669330                                                                             n7 = 1.846660                                                                             ν7 = 23.8                              r11 = -12.08426                                                                          d11 = 4.358284                                                     r12 = -6.61021                                                                           d12 = 3.807170                                                                             n8 = 1.846660                                                                             ν8 = 23.8                              r13 = -10.66959                                                                          d13 = 4.004968                                                                             n9 = 1.772499                                                                             ν9 = 49.6                              r14 = -10.95412                                                                          d14 = 3.679284                                                     r15 = -13.63092                                                                          d15 = 8.940710                                                                            n10 = 1.729157                                                                            ν10 = 54.7                              r16 = -11.40751                                                                          d16 = 9.956806                                                     r17 = 18.08889                                                                           d17 = 37.945337                                                                           n11 = 1.516330                                                                            ν11 = 64.1                              r18 = -8.56598                                                                           d18 = 6.671087                                                                            n12 = 1.850259                                                                            ν12 = 32.3                              r19 = -23.41526                                                                          d19 = 0.300000                                                     r20 = 39.63203                                                                           d20 = 1.000000                                                                            n13 = 1.806098                                                                            ν13 = 40.9                              r21 = ∞                                                                            d21 = 5.000000                                                                            n14 = 1.516330                                                                            ν14 = 64.1                              r22 = ∞                                                                            d22 = 5.00 0000                                                                           n15 = 1.516330                                                                            ν15 = 64.1                              r23 = ∞                                                                            d22 = 1.000000                                                                            n16 = 1.806098                                                                            ν16 = 40.9                              r24 = -39.63203                                                                          d23 = 0.300000                                                     r25 = 23.41526                                                                           d25 = 6.671087                                                                            n17 = 1.850259                                                                            ν17 = 32.3                              r26 = 8.56598                                                                            d26 = 37.945337                                                                           n18 = 1.516330                                                                            ν18 = 64.1                              r27 = -18.08889                                                                          d27 = 10.000000                                                    r28 = 18.08889                                                                           d28 = 37.945337                                                                           n19 = 1.516330                                                                            ν19 = 64.1                              r29 = -8.56598                                                                           d29 = 6.671087                                                                            n20 = 1.850259                                                                            ν20 = 32.3                              r30 = -23.41526                                                                          d30 = 0.300000                                                     r31 = 39.63203                                                                           d31 = 1.000000                                                                            n21 = 1.806098                                                                            ν21 = 40.9                              r32 = ∞                                                                            d32 = 5.000000                                                                            n22 = 1.516330                                                                            ν22 = 64.1                              r33 = ∞                                                                            d33 = 5.000000                                                                            n21 = 1.516330                                                                            ν21 = 64.1                              r34 = ∞                                                                            d34 = 1.000000                                                                            n22 = 1.806098                                                                            ν22 = 40.9                              r35 = -39.63203                                                                          d35 = 0.300000                                                     r36 = 23.41526                                                                           d36 = 6.671087                                                                            n25 = 1.850259                                                                            ν25 = 32.3                              r37 = 8.56598                                                                            d37 = 37.945337                                                                           n26 = 1.516330                                                                            ν26 = 64.1                              r38 = -18.08889                                                                          d38 = 10.000000                                                    r39 = 18.08889                                                                           d39 = 37.945337                                                                           n27 = 1.516330                                                                            ν27 = 64.1                              r40 = -8.56598                                                                           d40 = 6.671087                                                                            n28 = 1.850259                                                                            ν28 = 32.3                              r41 = -23.41526                                                                          d41 = 0.300000                                                     r42 = 39.63203                                                                           d42 = 1.000000                                                                            n29 = 1.806098                                                                            ν29 = 40.9                              r43 = ∞                                                                            d43 = 5.000000                                                                            n30 = 1.516330                                                                            ν30 = 64.1                              r44 = ∞                                                                            d44 = 5.000000                                                                            n31 = 1.516330                                                                            ν31 = 64.1                              r45 = ∞                                                                            d45 = 1.000000                                                                            n32 = 1.806098                                                                            ν32 = 40.9                              r46 = -39.63203                                                                          d46 = 0.300000                                                     r47 = 23.41526                                                                           d47 = 6.671087                                                                            n33 = 1.850259                                                                            ν33 = 32.3                              r48 = 8.56598                                                                            d47 = 37.945337                                                                           n34 = 1.516330                                                                            ν34 = 64.1                              r49 = -18.08889                                                                          d49 = 15.000000                                                    r50 = -15.76035                                                                          d50 = 7.000000                                                                            n35 = 1.816000                                                                            ν35 = 46.6                              r51 = 10.49216                                                                           d51 = 0.300000                                                     r52 = 19.16924                                                                           d52 = 1.000000                                                                            n36 = 1.729157                                                                            ν36 = 54.7                              r53 = 10.37555                                                                           d53 = 1.000000                                                                            n37 = 1.755199                                                                            ν37 = 27.5                              r54 = 8.20791                                                                            d54 = 6.363656                                                     r55 = -24.61446                                                                          d55 = 3.366619                                                                            n38 = 1.592701                                                                            ν38 = 35.3                              r56 = 9.99541                                                                            d56 = 9.925109                                                                            n39 = 1.618000                                                                            ν39 = 63.4                              r57 = -27.28005                                                                          d57 = 0.547138                                                     r58 = 22.89857                                                                           d58 = 7.000000                                                                            n40 = 1.729157                                                                            ν40 = 54.7                              r59 =465.13444                                                                           d59 = 100.501554                                                   ______________________________________                                    

                  TABLE 12                                                        ______________________________________                                        Lens data of the twenty fifth embodiment                                      R          D           N           ν                                       ______________________________________                                         r1 = ∞                                                                             d1 = 0.400000                                                                             n1 = 1.769000                                                                             ν1 = 71.8                               r2 = ∞                                                                             d2 = 0.300000                                                      r3 = -5.97394                                                                            d3 = 0.500000                                                                             n2 = 1.784720                                                                             ν2 = 25.8                               r4 = -81.88587                                                                           d4 = 0.400000                                                      r5 = ∞                                                                             d5 = 7.000000                                                                             n3 = 1.806098                                                                             ν3 = 40.9                               r6 = ∞                                                                             d6 = 0.000000                                                                             n4 = 1.806098                                                                             ν4 = 40.9                               r7 = ∞                                                                             d7 = 5.000000                                                                             n5 = 1.806098                                                                             ν5 = 40.9                               r8 = -19.02807                                                                           d8 = 0.300000                                                      r9 = 19.68776                                                                            d9 = 1.500000                                                                             n6 = 1.603112                                                                             ν6 = 60.7                              r10 = -143.32901                                                                         d10 = 0.300000                                                     r11 = 8.84970                                                                            d11 = 2.000000                                                                             n7 = 1.603112                                                                             ν7 = 60.7                              r12 = 205.54794                                                                          d12 = 2.000000                                                                             n8 = 1.846660                                                                             ν8 = 23.8                              r13 = 7.54926                                                                            d13 = 3.000000                                                     r14 = 11.00667                                                                           d14 = 3.000000                                                                             n9 = 1.846660                                                                             ν9 = 23.8                              r15 = 6.70344                                                                            d15 = 2.697123                                                                            n10 = 1.603112                                                                            ν10 = 60.7                              r16 = -29.22995                                                                          d16 = 0.300000                                                     r17 = 25.03133                                                                           d17 = 5.000000                                                                            n11 = 1.729157                                                                            ν11 = 54.7                              r18 = -19.09934                                                                          d18 = 14.067359                                                    r19 = 20.97714                                                                           d19 = 31.002854                                                                           n12 = 1.516330                                                                            ν12 = 64.1                              r20 = -9.61884                                                                           d20 = 1.000000                                                                            n13 = 1.850259                                                                            ν13 = 32.3                              r21 = -18.35394                                                                          d21 = 0.300000                                                     r22 = 39.59182                                                                           d22 = 1.000000                                                                            n14 = 1.806098                                                                            ν14 = 40.9                              r23 = ∞                                                                            d23 = 12.733214                                                                           n15 = 1.516330                                                                            ν15 = 64.1                              r24 = ∞                                                                            d24 = 12.733214                                                                           n16 = 1.516330                                                                            ν16 = 64.1                              r25 = ∞                                                                            d25 = 1.000000                                                                            n17 = 1.806098                                                                            ν17 = 40.9                              r26 = -39.59182                                                                          d26 = 0.300000                                                     r27 = 18.35394                                                                           d27 = 1.000000                                                                            n18 = 1.850259                                                                            ν18 = 32.3                              r28 = 9.61884                                                                            d28 = 31.002854                                                                           n19 = 1.516330                                                                            ν19 = 64.1                              r29 = -20.97714                                                                          d29 = 13.999522                                                    r30 = 20.97714                                                                           d30 = 31.002854                                                                           n20 = 1.516330                                                                            ν20 = 64.1                              r31 = -9.61884                                                                           d31 = 1.000000                                                                            n21 = 1.850259                                                                            ν21 = 32.3                              r32 = -18.35394                                                                          d32 = 0.300000                                                     r33 = 39.59182                                                                           d33 = 1.000000                                                                            n22 = 1.806098                                                                            ν22 = 40.9                              r34 = ∞                                                                            d34 = 12.733214                                                                           n23 = 1.516330                                                                            ν23 = 64.1                              r35 = ∞                                                                            d35 = 12.733214                                                                           n24 = 1.516330                                                                            ν24 = 64.1                              r36 = ∞                                                                            d36 = 1.000000                                                                            n25 = 1.806098                                                                            ν25 = 40.9                              r37 = -39.59182                                                                          d37 = 0.300000                                                     r38 = 18.35394                                                                           d38 = 1.000000                                                                            n26 = 1.850259                                                                            ν26 = 32.3                              r39 = 9.61884                                                                            d39 = -31.002854                                                                          n27 = 1.516330                                                                            ν27 = 64.1                              r40 = -20.97714                                                                          d40 = 22.951000                                                    r41 = 51.24000                                                                           d41 = 4.900000                                                                            n28 = 1.712995                                                                            ν28 = 53.9                              r42 = -30.80800                                                                          d42 = 0.350000                                                     r43 = 15.16600                                                                           d43 = 4.930000                                                                            n29 = 1.617001                                                                            ν29 = 62.8                              r44 = 4.26000                                                                            d44 = 1.650000                                                                            n30 = 1.592701                                                                            ν30 = 35.3                              r45 = 10.61000                                                                           d45 = 7.000000                                                     r46 = -8.87100                                                                           d46 = 2.070000                                                                            n31 = 1.755199                                                                            ν31 = 27.5                              r47 = -42.79500                                                                          d47 = 7.380000                                                                            n32 = 1.696800                                                                            ν32 = 56.5                              r48 = -13.94800                                                                          d48 = 0.480000                                                     r49 = ∞                                                                            d49 = 4.700000                                                                            n33 = 1.804000                                                                            ν34 = 46.6                              r50 = -45.75100                                                                          d50 = 8.660000                                                     r51 = 47.10400                                                                           d51 = 3.500000                                                                            n34 = 1.516330                                                                            ν34 = 64.1                              r52 = -22.01500                                                                          d52 = 1.500000                                                                            n35 = 1.784718                                                                            ν35 = 25.7                              r53 = -48.13700                                                                          d53 = 1.000000                                                     r54 = 79.15800                                                                           d54 = 3.000000                                                                            n36 = 1.572501                                                                            ν36 = 57.8                              r55 = -79.15800                                                                          d55 = 32.098487                                                    ______________________________________                                    

                  TABLE 13                                                        ______________________________________                                        Lens data of the twenty sixth embodiment                                      ______________________________________                                         r1 = ∞                                                                             d1 = 1.0    n1 = 1.51633                                                                              ν1 = 64.15                              r2 = ∞                                                                             d2 = 0.3                                                           r3 = ∞                                                                             d3 = 1.5    n2 = 1.72916                                                                              ν2 = 54.68                              r4 = 4.4560                                                                              d4 = 2.5                                                           r5 = ∞                                                                             d5 = 22.02  n3 = 1.88300                                                                              ν3 = 40.78                              r6 = ∞ (pupil)                                                                     d6 = 5.39   n4 = 1.88300                                                                              ν4 = 40.78                              r7 = -10.3990                                                                            d7 = 1.02                                                          r8 = -8.6190                                                                             d8 = 2.0    n5 = 1.62004                                                                              ν5 = 36.25                              r9 = ∞                                                                             d9 = 3.5    n6 = 1.788  ν6 = 47.38                             r10 = -14.1680                                                                           d10 = 2.28                                                         r11 = 24.1810                                                                            d11 = 6.14   n7 = 1.51633                                                                              ν7 = 64.15                             r12 = -11.7470                                                                           d12 = 3.0    n8 = 1.78472                                                                              ν8 = 25.71                             r13 = ∞                                                                            d13 = 8.65                                                         r14 = 38.2890                                                                            d14 = 3.0    n9 = 1.59551                                                                              ν9 = 39.21                             r15 = 11.4220                                                                            d15 = 6.0   n10 = 1.51633                                                                             ν10 = 64.15                             r16 = -19.2720                                                                           d16 = 10.0                                                         ______________________________________                                    

                  TABLE 14                                                        ______________________________________                                        Lens data of the twenty seventh embodiment                                    ______________________________________                                         r1 = ∞                                                                             d1 = 0.4    n1 = 1.7682                                                                               ν1 = 71.8                               r2 = ∞                                                                             d2 = 0.5                                                           r3 = -12.44196                                                                           d3 = 0.5    n2 = 1.883  ν2 = 40.8                               r4 = 3.50665                                                                             d4 = 0.4                                                           r5 = ∞                                                                             d5 = 7.0    n3 = 1.80610                                                                              ν3 = 40.9                               r6 = ∞ (pupil)                                                                     d6 = 7.0    n4 = 1.80610                                                                              ν4 = 40.9                               r7 = -9.32306                                                                            d7 = 0.3                                                           r8 = 24.40418                                                                            d8 = 1.3301                                                                               n5 = 1.60311                                                                              ν5 = 60.7                               r9 = -51.70650                                                                           d9 = 0.8047                                                       r10 = 10.49630                                                                           d10 = 10.0   n6 = 1.60311                                                                              ν6 = 60.7                              r11 = -12.17332                                                                          d11 = 1.0    n7 = 1.84666                                                                              ν7 = 23.8                              r12 = 5.56286                                                                            d12 = 1.7183                                                       r13 = -11.69704                                                                          d13 = 1.0    n8 = 1.84666                                                                              ν8 = 23.8                              r14 = -221.94536                                                                         d14 = 2.1568                                                                               n9 = 1.60311                                                                              ν9 = 60.7                              r15 = -8.24002                                                                           d15 = 0.3                                                          r16 = 10.31164                                                                           d16 = 2.3746                                                                              n10 = 1.72916                                                                             ν10 = 54.7                              r17 = -30.38097                                                                          d17 = 12.0                                                         r18 = 20.97714                                                                           d18 = 31.0029                                                                             n11 = 1.51633                                                                             ν11 = 64.1                              r19 = -9.61884                                                                           d19 = 1.0   n12 = 1.85026                                                                             ν12 = 32.3                              r20 = -18.35394                                                                          d20 = 0.3                                                          r21 = 39.59182                                                                           d21 = 1.0   n13 = 1.8061                                                                              ν13 = 40.9                              r22 = ∞                                                                            d22 = 25.4664                                                                             n14 = 1.51633                                                                             ν14 = 64.1                              r23 = ∞                                                                            d22 = 1.0   n15 = 1.8061                                                                              ν15 = 40.9                              r24 = -39.59182                                                                          d23 = 0.3                                                          r25 = 18.35394                                                                           d25 = 1.0   n16 = 1.85026                                                                             ν16 = 32.3                              r26 = 9.61884                                                                            d26 = 31.0029                                                                             n17 = 1.51633                                                                             ν17 = 64.1                              r27 = -20.97714                                                                          d27 = 13.9995                                                      r28 = 20.97714                                                                           d28 = 31.0029                                                                             n18 = 1.51633                                                                             ν18 = 64.1                              r29 = -9.61884                                                                           d29 = 1.0   n19 = 1.85026                                                                             ν19 = 32.3                              r30 = -18.35394                                                                          d30 = 0.3                                                          r31 = 39.59182                                                                           d31 = 1.0   n20 = 1.8061                                                                              ν20 = 40.9                              r32 = ∞                                                                            d32 = 25.4664                                                                             n21 = 1.51633                                                                             ν21 = 64.1                              r33 = ∞                                                                            d33 = 1.0   n22 = 1.8061                                                                              ν22 = 40.9                              r34 = -39.59182                                                                          d34 = 0.3                                                          r35 = 18.35394                                                                           d35 = 1.0   n23 = 1.85026                                                                             ν23 = 32.3                              r36 = 9.61884                                                                            d36 = 31.0029                                                                             n24 = 1.51633                                                                             ν24 = 64.1                              r37 = -20.97714                                                                          d37 = 13.9995                                                      r38 = 20.97714                                                                           d38 = 31.0029                                                                             n25 = 1.51633                                                                             ν25 = 64.1                              r39 = -9.61884                                                                           d39 = 1.0   n26 = 1.85026                                                                             ν26 = 32.3                              r40 = -18.35394                                                                          d40 = 0.3                                                          r41 = 39.59182                                                                           d41 = 1.0   n27 = 1.8061                                                                              ν27 = 40.9                              r42 = ∞                                                                            d42 = 25.4664                                                                             n28 = 1.51633                                                                             ν28 = 64.1                              r43 = ∞                                                                            d43 = 1.0   n29 = 1.8061                                                                              ν29 = 40.9                              r44 = -39.59182                                                                          d44 = 0.3                                                          r45 = 18.35394                                                                           d45 = 1.0   n30 = 1.85026                                                                             ν30 = 32.3                              r46 = 9.6188.4                                                                           d46 = 31.0029                                                                             n31 = 1.51633                                                                             ν31 = 64.1                              r47 = -20.97714                                                                          d47 = 7.004                                                        ______________________________________                                    

What is claimed is:
 1. A stereoendoscope, comprising:an elongateinserted section having a distal end; an illuminating light projectingmeans for projecting an illuminating light from the distal end of saidinserted section; an objective optical system arranged on the distal endof said inserted section for forming the light from the objectilluminated by said illuminating light as a plurality of images having aparallax between them through a plurality of incident pupils; and oneimage transmitting optical system comprising one relay lens opticalsystem contained at least partially within said inserted section fortransmitting said plurality of images having a parallax between them bysaid objective optical system, wherein said objective optical system isformed of two negative lens units arranged in parallel with each otherand one positive lens group, said two negative lens units being arrangedto be substantially symmetrically concentric about an optical axis ofsaid one positive lens group and said image transmitting optical system,said two negative lens units being arranged nearer the object side ofsaid distal end of said inserted section than said one positive lensgroup.
 2. A stereoendoscope, comprising:an elongate inserted sectionhaving a distal end; an illuminating light projecting means forprojecting an illuminating light from the distal end of said insertedsection; an objective optical system arranged on the distal end of saidinserted section for forming a plurality of images having a parallaxbetween them such that they are substantially superimposed on oneanother of the object illuminated by said illuminating light; and oneimage transmitting optical system comprising one relay lens opticalsystem for transmitting said plurality of images; wherein said objectiveoptical system comprises a plurality of front lens groups and one rearlens group positioned proximally of said plurality of front lens groups.3. A stereoendoscope according to claim 2, comprising:a pupil dividingand image forming means for separating and forming said plurality ofimages having a parallax between them formed such that they aresubstantially superimposed on each other on a final image surface bysaid image transmitting optical system; and at least one image takingmeans for taking the images formed by said pupil dividing and imageforming means.
 4. A stereoendoscope according to claim 3,wherein saidplurality of front lens groups are formed of a negative power elementand a positive power element, said negative power element being arrangednearer the object side of said distal end of said inserted section thanis said positive power element.
 5. A stereoendoscope according to claim3 having an adapter optical system for separating and reforming theplurality of images having a parallax between them and made such thatthey are substantially superimposed on one another on a final imagesurface of said image transmitting optical system.
 6. A stereoendoscopeaccording to claim 3, wherein said plurality of images aresimultaneously spatially separated by said pupil dividing and imageforming means.
 7. A stereoendoscope according to claim 3, wherein saidplurality of images are alternatively formed in a time-sequential mannerby said pupil dividing and image forming means.
 8. A stereoendoscopeaccording to claim 2,wherein the space between said plurality of frontlens groups and said rear lens group is afocal.
 9. A stereoendoscope,comprising:an elongate inserted section having a distal end; anilluminating light projecting means for projecting an illuminating lightfrom the distal end of said inserted section; an objective opticalsystem wherein a plurality of optical systems are arranged in parallelon the distal end of said inserted section and a plurality of imageshaving a parallax between them are formed of the object illuminated bysaid illuminating light; an image transmitting optical system comprisingone relay lens optical system for transmitting the plurality of imagesformed by said objective optical system; and an image taking means fortaking at least two images of the plurality of images transmitted bysaid image transmitting optical system, wherein said objective opticalsystem comprises a plurality of front lens group optical systems whichare arranged in parallel, and a rear lens group optical system, whereinsaid plurality of front lens group optical systems is arranged to besubstantially symmetrically concentric about the optical axis of saidrear lens group optical system and said image transmitting opticalsystem, said objective optical system forming images of the beams fromsaid plurality of front lens group optical systems in substantiallysuperimposed positions, said image transmitting optical systemtransmitting a substantially superimposed plurality of images having aparallax between them formed by said objective optical system.
 10. Astereoendoscope according to claim 9, wherein positions of pupilstransmitted by said image transmitting optical system are separated fromeach other.
 11. A stereoendoscope according to claims 9, wherein a beamprojected from said plurality of front lens group optical systems is asubstantially afocal beam.
 12. A stereoendoscope according to claim 9,wherein said plurality of front lens group optical systems are arrangedmore on the object side than said rear group optical system and areseparated more from said rear group optical system than from a frontside focus position of said rear group optical system.
 13. Astereoendoscope comprising:an elongate inserted section having a distalend; an illuminating light projecting means for projecting anilluminating light from the distal end of said inserted section; anobjective optical system arranged with the distal end of said insertedsection; and an image taking means arranged within said inserted sectionfor taking the object image formed by said objective optical system,said objective optical system having two negative lens units arranged inparallel with each other and one positive lens group opposed to said twonegative lens units, said two negative lens units being arrangedsymmetrically concentric about the central axis of said positive lensgroup, said two negative lens units being arranged nearer the objectside of said distal end of said inserted section than is said positivelens group.